WO2019172589A1 - Wireless communication method using wake-up radio and wireless communication terminal therefor - Google Patents

Abstract

Disclosed is a wireless communication terminal which communicates wirelessly. The wireless communication terminal comprises: a first wireless transceiver for transmitting or receiving a signal by using a first waveform; a second wireless receiver for receiving a signal by using a second waveform different from the first waveform; and a processor. The processor: receives, through the second wireless receiver, a first wake-up radio (WUR) frame from a base wireless communication terminal in a basic service set (BSS) to which the wireless communication terminal belongs; when an identifier field in the first WUR frame indicates a transmitter ID that identifies the base wireless communication terminal, determines whether the wireless communication terminal is a recipient intended by the first WUR frame according to whether the BSS is a BSS corresponding to a multi-BSS identifier (BSSID) set; and when the wireless communication terminal is the recipient intended by the first WUR frame, wakes up the first wireless transceiver on the basis of the first WUR frame.

Description

Wireless communication method and wireless communication terminal using wake-up radio

The present invention relates to a method for improving transmission efficiency, and more particularly, to a wireless communication method and a wireless communication terminal using a wake-up radio in a WLAN.

Recently, with the expansion of mobile devices, wireless LAN technology that can provide a fast wireless Internet service to them is receiving a lot of attention. WLAN technology is a technology that enables wireless devices such as smart phones, smart pads, laptop computers, portable multimedia players, and embedded devices to wirelessly access the Internet at home, enterprise, or a specific service area based on wireless communication technology at a short range. to be.

Since IEEE (Institute of Electrical and Electronics Engineers) 802.11 supports the initial wireless LAN technology using the 2.4GHz frequency, various standards of technology are being put into practice or being developed. First, IEEE 802.11b supports communication speeds up to 11Mbps while using frequencies in the 2.4GHz band. IEEE 802.11a, commercialized after IEEE 802.11b, reduces the impact of interference compared to the frequency of the congested 2.4 GHz band by using the frequency of the 5 GHz band instead of the 2.4 GHz band. Up to 54Mbps. However, IEEE 802.11a has a shorter communication distance than IEEE 802.11b. And IEEE 802.11g, like IEEE 802.11b, uses a frequency of 2.4 GHz band to realize a communication speed of up to 54 Mbps and satisfies backward compatibility, which has received considerable attention. Is in the lead.

In addition, IEEE 802.11n is a technical standard established to overcome the limitation of communication speed, which has been pointed out as a weak point in WLAN. IEEE 802.11n aims to increase the speed and reliability of networks and to extend the operating range of wireless networks. More specifically, IEEE 802.11n supports High Throughput (HT) with data throughput of up to 540 Mbps and also uses multiple antennas at both the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology. In addition, the specification may use a coding scheme that transmits multiple duplicate copies to increase data reliability.

As the spread of wireless LANs is activated and applications are diversified, there is a need for a new wireless LAN system to support higher throughput (VHT) than the data throughput supported by IEEE 802.11n. It became. Among them, IEEE 802.11ac supports a wide bandwidth (80MHz to 160MHz) at 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but for backwards compatibility with existing 2.4GHz band products, early 11ac chipsets will also support operation in the 2.4GHz band. Theoretically, this specification allows multiple stations to have a minimum WLAN speed of 1 Gbps and a maximum single link speed of at least 500 Mbps. This is accomplished by extending the 802.11n concept of wireless interfaces, including wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to eight), multi-user MIMO, and higher density modulation (up to 256 QAM). In addition, IEEE 802.11ad is a method of transmitting data using a 60 GHz band instead of the existing 2.4 GHz / 5 GHz. IEEE 802.11ad is a transmission standard that uses beamforming technology to provide speeds of up to 7Gbps, and is suitable for streaming high bitrate video such as large amounts of data or uncompressed HD video. However, the 60 GHz frequency band is difficult to pass through obstacles, and thus can be used only between devices in a short space.

On the other hand, as the next generation wireless LAN standard after 802.11ac and 802.11ad, a discussion for providing a high-efficiency and high-performance wireless LAN communication technology in a high-density environment continues. That is, in a next generation WLAN environment, high frequency efficiency communication should be provided indoors / outdoors in the presence of a high density station and an access point (AP), and various technologies are required to implement this.

In addition, while developing technology to increase the speed and efficiency of wireless LAN, to extend the battery life of mobile devices equipped with wireless LAN, and to install wireless LAN on devices that operate based on very limited strategic sources such as batteries, There is a need to develop an efficient WLAN power saving technique. Previously proposed WLAN power saving schemes are methods in which devices enter a sleep mode to reduce power. In this case, the higher the power saving efficiency of the device, the more the device wakes up in a longer cycle. There is a disadvantage of delay. In order to solve this problem, a study on a power saving technique using a separate low strategy wake-up receiver is needed.

As described above, an object of the present invention is to perform a power saving operation by using a low power wake-up receiver in a wireless LAN environment.

In a wireless communication terminal wirelessly according to an embodiment of the present invention, a first wireless transceiver for transmitting and receiving a signal through a first waveform (waveform), receiving a signal through a second waveform different from the first waveform And a second wireless receiver and a processor. The processor may receive a first WUR frame from the base wireless communication terminal of a basic service set (BSS) to which the wireless communication terminal belongs, through the second wireless receiver, and When the identifier field of the first WUR frame indicates a sender ID for identifying the base wireless communication terminal, the wireless communication terminal determines whether the BSS corresponds to a BSS corresponding to a multiple BSS identifier (BSSID) set. If it is determined that the intended receiver of the 1 WUR frame, and the wireless communication terminal is the intended receiver of the first WUR frame, it is possible to wake up the first wireless transceiver based on the first WUR frame. The multiple BSSID set may be operated by one base wireless communication terminal and include a BSSID of each of a plurality of BSSs sharing an operating channel.

If the BSS to which the wireless communication terminal belongs does not correspond to the multiple BSSID set, the processor determines that the wireless communication terminal is an intended recipient of the first WUR frame, and the BSS to which the wireless communication terminal belongs is determined. If it corresponds to any one of the untransmitted BSSIDs included in the multiple BSSID set, it may be determined that the wireless communication terminal is not the intended recipient of the first WUR frame. The multi-BSSID set is composed of one transmitting BSSID and at least one untransmitted BSSID, and the transmitting BSSID is a representative BSSID used for transmission of a management frame for all of the plurality of BSSs operated by the base wireless communication terminal. The transmission is performed through the first waveform, and the at least one untransmitted BSSID may be a BSSID excluding a transmission BSSID among BSSIDs constituting the multiple BSSID set.

When the BSS to which the wireless communication terminal belongs corresponds to any one of the untransmitted BSSIDs included in the multiple BSSID set, the processor is further configured to perform the wireless communication based on an untransmitted ID for identifying a BSS to which the wireless communication terminal belongs. It may be determined whether the terminal is an intended recipient of the first WUR frame.

The processor may obtain an untransmitted ID for identifying a BSS to which the wireless communication terminal belongs based on the sender ID.

The processor receives, via the first wireless transceiver, BSSID index information corresponding to a BSS to which the wireless communication terminal belongs, and based on the BSSID index information and the sender ID corresponding to the BSS to which the wireless communication terminal belongs, The non-transmitted ID can be obtained.

The BSSID index information corresponding to the BSS to which the wireless communication terminal belongs may represent any one of integers from 1 to K. In this case, the processor determines that the wireless communication terminal is an intended recipient of the first WUR frame when the identifier field of the first WUR frame indicates a value obtained by adding the value indicated by the BSSID index information to the sender ID. can do.

The K may indicate the number of the untransmitted BSSIDs among the BSSIDs constituting the multiple BSSID set.

The processor may obtain the transmission BSSID through the first radio transceiver, and obtain the sender ID based on the transmission BSSID.

The sender ID may be a value set based on a predetermined number of least significant bits (LSBs) among a plurality of bits constituting the transmission BSSID.

The processor may receive a second WUR frame periodically transmitted through the second wireless receiver, and if the frame type field of the second WUR frame indicates a beacon, an identifier of the second WUR frame. Determine whether the wireless communication terminal is an intended recipient of the second WUR frame based on a field and the sender ID, and if the wireless communication terminal is an intended recipient of the second WUR frame, based on the second WUR frame A subsequent operation indicated by the second WUR frame can be performed.

The processor determines that the wireless communication terminal is an intended recipient of the second WUR frame when the identifier field of the second WUR frame includes the sender ID, and wherein the wireless communication terminal is the second WUR frame. If the intended recipient of the, it is possible to update the time information of the wireless communication terminal.

When the identifier field of the first WUR frame indicates the untransmitted ID, the first WUR frame may be a WUR frame broadcast through the second waveform in a BSS to which the wireless communication terminal belongs.

The identifier field of the first WUR frame includes one identifier represented by a predetermined number of bits, and the first WUR frame is a fixed length frame that does not include an additional field including another identifier besides the identifier field. Can be. The preset number may be 12.

The processor generates a frame check sequence (FCS) value based on values of a plurality of fields included in the first WUR frame when the wireless communication terminal is an intended recipient of the first WUR frame. And determining whether the first WUR frame is valid based on the generated FCS value and the value included in the FCS field, and if the first WUR frame is valid, based on the first WUR frame. The transceiver can be woken up.

According to an embodiment of the present invention, a method of operating a wireless communication terminal that transmits and receives a signal through a first waveform and receives a signal through a second waveform different from the first waveform includes the wireless communication terminal. Receiving a WUR frame (wake-up radio frame) via the second waveform from a base wireless communication terminal of a basic service set (BSS); When the identifier field of the WUR frame indicates a sender ID for identifying the base wireless communication terminal, the wireless communication terminal determines whether the WUR frame corresponds to a BSS corresponding to a set of BSS identifiers (BSSIDs). Determining if the intended recipient of the; And if the wireless communication terminal is the intended recipient of the WUR frame, waking up the wireless communication terminal based on the WUR frame. The multiple BSSID set may be operated by one base wireless communication terminal and include a BSSID of each of a plurality of BSSs sharing an operating channel.

The Wake-Up Receiver performs an efficient power-saving operation in the WLAN, and can efficiently proceed with subsequent data exchange sequences after the device wakes up.

1 illustrates a WLAN system according to an embodiment of the present invention.

2 illustrates an independent BSS, which is a wireless LAN system according to another embodiment of the present invention.

3 is a block diagram showing the configuration of a station according to an embodiment of the present invention.

4 is a block diagram illustrating a configuration of an access point according to an embodiment of the present invention.

5 schematically illustrates a process of establishing a link with an AP by an station according to an embodiment of the present invention.

6 and 7 are diagrams illustrating a network including a wireless communication terminal supporting WUR-based power save according to an embodiment of the present invention.

8 is a diagram illustrating a method for a wireless communication terminal and a base wireless communication terminal to negotiate a WUR-related operation and to perform a WUR-related operation according to an embodiment of the present invention.

9 illustrates a configuration of a WUR capability element according to an embodiment of the present invention.

10 illustrates a configuration of a WUR operation element according to an embodiment of the present invention.

11 shows an example configuration of a WUR action frame and an example configuration of a WUR mode element.

12 illustrates a format of a WUR PPDU (PCLP Protocol Data Unit) according to an embodiment of the present invention.

13 illustrates a specific format of a WUR frame according to an embodiment of the present invention.

14 illustrates a WUR identifier space according to an embodiment of the present invention.

15 is a diagram illustrating a method of obtaining a TXID based on a BSSID of a base wireless communication terminal according to an embodiment of the present invention.

16 is a diagram illustrating a method of obtaining a TXID according to another embodiment of the present invention.

17 is a diagram illustrating a method of obtaining a TXID according to another embodiment of the present invention.

18 illustrates a WUR group ID space according to an embodiment of the present invention.

19 is a diagram illustrating a method for receiving a WUR beacon frame by a wireless communication terminal according to an embodiment of the present invention.

20 is a diagram illustrating a method for transmitting a WUR A-beacon according to an embodiment of the present invention.

21 is a diagram illustrating a method for reporting a superimposed WUR identifier by a wireless communication terminal according to one embodiment of the present invention.

22 illustrates a structure of a WUR ID element according to an embodiment of the present invention.

23 is a diagram illustrating a power save operation of a wireless communication terminal according to an embodiment of the present invention.

24 is a diagram illustrating a detailed operation of wake-up of a wireless communication terminal according to an embodiment of the present invention.

25 is a diagram illustrating WUR duty-cycle operation of a wireless communication terminal according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a configuration is “connected” to another configuration, this includes not only “directly connected” but also “electrically connected” with other components in between. do. In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated. In addition, limitations of “above” or “below” based on a particular threshold may be appropriately replaced with “over” or “less than”, respectively, according to embodiments.

1 illustrates a WLAN system according to an embodiment of the present invention. The WLAN system includes one or more Basic Service Sets (BSSs), which represent a set of devices that can successfully synchronize and communicate with each other. In general, the BSS may be classified into an infrastructure BSS (Independent BSS) and an Independent BSS (IBSS), and FIG. 1 illustrates an infrastructure BSS.

As shown in FIG. 1, the infrastructure BSSs BSS1 and BSS2 are configured to provide one or more stations STA-1, STA-2, STA-3, STA-4, STA-5, and Distribution Service. A distribution system (DS) that connects access points (PCP / AP-1, PCP / AP-2) that are providing stations, and a plurality of access points (PCP / AP-1, PCP / AP-2) Include.

A station (STA) is any device that includes a medium access control (MAC) compliant with the IEEE 802.11 standard and a physical layer interface to a wireless medium. This includes both access points (APs) as well as non-AP stations. In addition, in the present specification, the term “terminal” may be used as a concept including both a station and an WLAN communication device such as an AP. The station for wireless communication includes a processor and a transceiver, and may further include a user interface unit and a display unit according to an embodiment. The processor may generate a frame to be transmitted through the wireless network or process a frame received through the wireless network, and may perform various processing for controlling the station. The transceiver is functionally connected to the processor and transmits and receives a frame through a wireless network for the station.

Receiving a frame or packet in the present disclosure may mean successful reception. For example, successful reception may mean reception that is determined not to fail based on a frame check sequence (FCS) included in a frame or packet.

An Access Point (AP) is an entity that provides access to a Distribution System (DS) via a wireless medium for a station associated with it. In the infrastructure BSS, communication between non-AP stations is performed via an AP. However, when a direct link is established, direct communication between non-AP stations is possible. Meanwhile, in the present disclosure, the AP is used as a concept including a personal BSS coordination point (PCP), and is broadly a centralized controller, a base station (BS), a node-B, a base transceiver system (BTS), or a site. It can include all the concepts such as a controller. The plurality of infrastructure BSSs may be interconnected through a distribution system (DS). At this time, the plurality of BSSs connected through the distribution system is referred to as an extended service set (ESS).

2 illustrates an independent BSS, which is a wireless LAN system according to another embodiment of the present invention. In the exemplary embodiment of FIG. 2, the same or corresponding parts as those of the exemplary embodiment of FIG. 1 may be omitted.

Since the BSS-3 shown in FIG. 2 is an independent BSS and does not include an AP, all stations STA-6 and STA-7 are not connected to the AP. Independent BSSs do not allow access to the distribution system and form a self-contained network. In the independent BSS, the respective stations STA-6 and STA-7 may be directly connected to each other.

3 is a block diagram showing the configuration of a station 100 according to an embodiment of the present invention.

As shown, the station 100 according to an embodiment of the present invention includes a processor 110, a network interface card (NIC) 120, a user interface unit 140, a display unit 150, and a memory 160. It may include.

First, the network interface card 120 is a module for performing a WLAN connection and performs frame transmission and reception for the station 100. The network interface card 120 may be embedded in the station 100 or externally provided, and may include at least one network interface card module using different frequency bands according to an exemplary embodiment. For example, the network interface card may include network interface card modules of different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. According to an embodiment, the station 100 may include a network interface card module using a frequency band of 6 GHz or more and a network interface card module using a frequency band of 6 GHz or less. Each network interface card module may perform wireless communication with an AP or an external station according to a wireless LAN standard of a frequency band supported by the corresponding network interface card module. The network interface card 120 may operate only one network interface card module at a time or simultaneously operate a plurality of network interface card modules according to the performance and requirements of the station 100. When the station 100 includes a plurality of network interface card modules, each network interface card module may be provided in an independent form, or may be integrated into one chip.

Next, the user interface unit 140 includes various types of input / output means provided in the station 100. That is, the user interface unit 140 may receive a user input using various input means, and the processor 110 may control the station 100 based on the received user input. In addition, the user interface 140 may perform an output based on a command of the processor 110 using various output means.

Next, the display unit 150 outputs an image on the display screen. The display unit 150 may output various display objects such as a content executed by the processor 110 or a user interface based on a control command of the processor 110. In addition, the memory 160 stores a control program used in the station 100 and various data according thereto. Such a control program may include an access program necessary for the station 100 to perform an access with an AP or an external station.

The processor 110 of the present invention may execute various instructions or programs and process data in the station 100. In addition, the processor 110 may control each unit of the station 100 described above, and may control data transmission and reception between the units. According to an embodiment of the present invention, the processor 110 may execute a program for accessing the AP stored in the memory 160 and receive a communication setup message transmitted by the AP. In addition, the processor 110 may read information on the priority condition of the station 100 included in the communication configuration message, and request a connection to the AP based on the information on the priority condition of the station 100. One specific embodiment thereof will be described later.

The station 100 shown in FIG. 3 is a block diagram according to an embodiment of the present invention, in which blocks marked separately represent logical elements of devices. Therefore, the elements of the above-described device may be mounted in one chip or in a plurality of chips according to the design of the device. In addition, in one embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, may be selectively provided in the station 100.

4 is a block diagram illustrating a configuration of an access point (hereinafter, referred to as an "AP") 200 according to an embodiment of the present invention.

As shown, the AP 200 according to an embodiment of the present invention may include a processor 210, a network interface card 220, and a memory 260. In FIG. 4, overlapping descriptions of parts identical or corresponding to those of the station 100 of FIG. 3 will be omitted.

Referring to FIG. 4, an AP 200 according to the present disclosure includes a network interface card 220 for operating a BSS in at least one frequency band. As described above in the embodiment of FIG. 3, the network interface card 220 of the AP 200 may also include a plurality of network interface card modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may include two or more network interface card modules of different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. Preferably, the AP 200 may include a network interface card module using a frequency band of 6 GHz or more, and a network interface card module using a frequency band of 6 GHz or less. Each network interface card module may perform wireless communication with a station according to a wireless LAN standard of a frequency band supported by the corresponding network interface card module. The network interface card 220 may operate only one network interface card module at a time or simultaneously operate a plurality of network interface card modules according to the performance and requirements of the AP 200.

Next, the memory 260 stores a control program used in the AP 200 and various data according thereto. Such a control program may include an access program for managing a connection of a station. In addition, the processor 210 may control each unit of the AP 200 and may control data transmission and reception between the units. According to an embodiment of the present invention, the processor 210 may execute a program for accessing a station stored in the memory 260 and transmit a communication setup message for one or more stations. In this case, the communication setting message may include information on the access priority condition of each station. In addition, the processor 210 performs connection establishment according to a connection request of a station. One specific embodiment thereof will be described later.

5 is a diagram schematically illustrating a process of establishing a link with an AP 200 by a station (STA) 100 according to an embodiment of the present invention.

Referring to FIG. 5, the link between the STA 100 and the AP 200 is largely established through three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 obtains access information of a BSS operated by the AP 200. As a method for scanning, a passive scanning method for obtaining information by using only a beacon message S101 periodically transmitted by the AP 200, and a STA 100 requests a probe to the AP. There is an active scanning method of transmitting a probe request (S103) and receiving a probe response from the AP (S105) to obtain access information.

The STA 100 that has successfully received the radio access information in the scanning step transmits an authentication request (S107a), receives an authentication response from the AP 200 (S107b), and performs an authentication step. do. After the authentication step is performed, the STA 100 transmits an association request (S109a), receives an association response from the AP 200 (S109b), and performs the association step. In the present specification, the association (association) basically means a wireless coupling, but the present disclosure is not limited thereto and the binding in the broad sense may include both wireless coupling and wired coupling.

Meanwhile, the 802.1X based authentication step S111 and the IP address obtaining step S113 through DHCP may be performed. In FIG. 5, the authentication server 300 is a server that processes 802.1X-based authentication with the STA 100 and may be physically coupled to the AP 200 or may exist as a separate server.

In a specific embodiment, the AP 200 may be a wireless communication terminal for allocating communication medium resources and scheduling in an independent network that is not connected to an external distribution service, such as an ad-hoc network. The AP 200 may be a base wireless communication terminal. In addition, the AP 200 may be at least one of a base station, an eNB, and a transmission point (TP).

The wireless communication terminal may stop transmitting / receiving a WLAN radio and receive a wake-up radio (hereinafter, “WUR”) to increase energy efficiency. In this case, the magnitude of power used for the wake-up radio transmission and reception may be smaller than the magnitude of power used for the WLAN signal transmission. A general WLAN radio distinguished from WUR may be referred to as a primary connectivity radio (PCR). A typical WLAN radio may represent a radio capable of transmitting and receiving a 20 MHz high-throughput (PPH) physical layer protocol data unit (PPDU) defined by IEEE 802.11.

In the existing power save mode (hereinafter, referred to as a "PS mode"), the wireless communication terminal may enter a PCR doze state that cuts off power supply for some functions including a PCR transmission and reception function. In addition, in the PS mode, the wireless communication terminal may enter the PCR awake state, which is a state capable of interrupting the PCR dose and performing PCR transmission and reception in order to receive a wireless signal from an external device. Resupplying power cut off by the wireless communication terminal in the PCR dose state is referred to as a PCR wake-up. In the conventional PS mode, the wireless communication terminal can wake up periodically to receive a wireless signal from an external device. This operation can lower the operation efficiency of the wireless communication terminal.

 When the wireless communication terminal wakes up according to the WUR signal for triggering the wake-up of the PCR transceiver, the operation efficiency of the wireless communication terminal can be improved. This power save operation is referred to as WUR based power save operation. The WUR-based power save operation allows the wireless communication terminal to reduce unnecessary wake-up operation. In addition, when using the WUR, it is possible to increase the time that the wireless communication terminal stays in the PCR dose state. Accordingly, the power efficiency of the wireless communication terminal can be increased. For the WUR-based power save operation, the wireless communication terminal may include a wake-up receiver (hereinafter, “WURx”) that operates at a lower power than the PCR transceiver. In addition, when the wireless communication terminal needs to transmit a WUR signal, the wireless communication terminal may include a wake-up transmitter.

Some of the WUR signal may be transmitted in a waveform different from the waveform of the PCR signal. For example, part of the WUR signal may be transmitted through OOK (On-Off Keying). In detail, the PCR transceiver may transmit and receive a modulated signal through a wave-form modulation method using a wave form different from the WURx. Hereinafter, an operation of a wireless communication terminal including WURx and a wireless communication method using WUR according to an embodiment of the present invention will be described.

6 and 7 are diagrams illustrating a network including a wireless communication terminal supporting WUR-based power save according to an embodiment of the present invention. Referring to FIG. 6, the network may include an AP and a station supporting WUR based power save. The AP may transmit a WUR frame to the WUR terminal. Here, the WUR frame may include at least one of a wake-up frame or a WUR beacon frame. Specifically, the AP may wake up the terminal by transmitting a wake-up frame to the WUR terminal. Unless otherwise specified in this specification, a frame represents a MAC frame. Meanwhile, the AP and the station of FIG. 6 may include a PCR transmission / reception function supporting at least any one of 802.11a / b / g / n / ac / ax, which is a general WLAN standard. In addition, the AP and the station of FIG. 6 may coexist in one network with a general station supporting only PCR transmission and reception without supporting WUR transmission and reception. For example, the network of FIG. 6 may include a general station that does not have a WUR function.

According to an embodiment, the AP may include a first radio transceiver (TR) that supports a communication method using PCR. The first wireless transceiver may transmit and receive a PPDU through PCR. The AP may include a second wireless transmitter that performs WUR PPDU transmission. The second wireless transmitter may be referred to as a wake-up transmitter (WUTx). Here, a part of the WUR signal may be a signal transmitted to a second waveform different from the first waveform used in the PCR signal. In detail, a part of the WUR signal may be transmitted through the OOK. For example, the second wireless transmitter may transmit a WUR PPDU to the station through the WUR. In addition, when the AP additionally includes a WURx, the AP may receive a WUR PPDU from the outside through the WURx.

Meanwhile, according to another exemplary embodiment, the first wireless transceiver and the second wireless transmitter may be implemented as one transceiver. For example, the AP may transmit and receive a PCR signal and transmit a WUR signal through one transceiver.

 As shown in FIG. 6, the AP may transmit a WUR PPDU including a wake-up frame that triggers a wake-up of the PCR transceiver of the station to a station that supports WUR-based power save. According to an embodiment, the AP may wake up only a station entering a WUR-based power save mode among a plurality of stations belonging to the BSS of the AP. In addition, when the station receives a wake-up frame that includes an identifier indicating the station, the station may wake up in a PCR dose state. For example, the WUR frame may include identification information identifying at least one station. The wake-up frame may include identification information identifying at least one station to wake up. When the first station receives a wake-up frame including identification information indicating the first station, the first station may wake up. In addition, a station other than the first station within the BSS of the AP or within another BSS may not wake up.

According to one embodiment, a station supporting WUR based power save may include a WURx for receiving the WUR part of the WUR PPDU. The station may include a WURx, which is a second wireless receiver separately from the first wireless transceiver that supports PCR transmission and reception. Here, the first wireless transceiver may be referred to as a PCR transceiver. The wireless communication terminal may transmit and receive a PCR signal using a PCR transceiver. The second wireless receiver may receive a signal transmitted to a second waveform different from the first waveform of the signal transmitted and received through the first wireless transceiver. The WURx may wake up the PCR transceiver by receiving a wake-up frame from the AP. When the WURx receives a wake-up frame while the station's PCR transceiver is operating in the PCR dose state, the WURx may wake up the PCR transceiver via an internal wake-up signal.

For example, the station may have an interface between the PCR transceiver and the WURx. At this time, the WURx may wake up the PCR transceiver of the station through the internal interface. Specifically, the WURx may wake up the PCR transceiver through an internal signal to the PCR transceiver, but is not limited thereto. For example, the station may have a processor that controls the overall operation of the station. In this case, the WURx may wake up the PCR transceiver through the processor. In detail, the station may cut off power of the PCR transceiver and the processor in the dose state. In this case, the WURx may stop the power cutoff of the processor by receiving the wake-up frame and may wake up the PCR transceiver through the processor.

According to an embodiment, the WURx may deliver the information received through the WUR frame to the PCR transceiver. The WURx may transmit information on the wake-up follow-up operation to the PCR transceiver through the internal interface. Specifically, the information about the subsequent operation may be a subsequent operation identifier (Sequence ID, SID) identifying the subsequent operation. In addition, the PCR transceiver may set parameters of the WURx required for the WUR-based power save operation through an internal interface.

For example, the WURx may include a wake-up preamble detector (WU preamble detector), a wireless communication terminal identifier detector (STA ID Detector), and a message parser. The WU preamble detector detects the WUR PPDU by identifying a signal pattern sequence included in the WUR PPDU. The WU preamble detector may perform AGC (Automatic Gain Control) and synchronization on the WUR signal based on the detected signal pattern sequence.

The wireless communication terminal identifier detector detects a recipient of the WUR frame. At this time, the receiver of the WUR frame indicates the receiver intended by the wireless communication terminal that transmitted the WUR frame. The wireless communication terminal identifier detector may acquire information for identifying a receiver of the corresponding WUR frame based on the WUR DATA of the WUR PPDU. The wireless communication terminal identifier detector may acquire information for identifying a receiver of the WUR frame based on the WUR SYNC and the WUR DATA of the WUR PPDU. WUR SYNC and WUR DATA of the WUR PPDU will be described later with reference to FIG. 8. The message parser parses the messages that the WUR frame contains. In more detail, the message parser may parse a message included in the WUR frame to obtain a message indicated by the WUR frame.

According to an embodiment, the wireless communication terminal may determine a condition for keeping the WUR PPDU available through the WURx of the wireless communication terminal. According to a specific embodiment, the wireless communication terminal may maintain the WURx in a state where it can be received until a specific condition is satisfied. For example, the wireless communication terminal may maintain the WURx in a state capable of transmitting and receiving until the wireless communication terminal recognizes that the wake-up of the PCR transceiver of the wireless communication terminal is successful.

For convenience of explanation, hereinafter, unless otherwise stated, the wireless communication terminal and the base wireless communication terminal will be described on the premise that they are a wireless communication terminal and a base wireless communication terminal that support power save based on WUR.

For the WUR-related operation, information exchange on whether the base radio communication terminal and the wireless communication terminal support the WUR operation and negotiation process for the WUR operation are required. The base wireless communication terminal and the wireless communication terminal may perform information exchange on whether to support the WUR operation and negotiate the WUR operation using PCR. This will be described with reference to FIG. 8.

8 is a diagram illustrating a method for a wireless communication terminal and a base wireless communication terminal to negotiate a WUR-related operation and to perform a WUR-related operation according to an embodiment of the present invention. The base wireless communication terminal and the wireless communication terminal may perform information exchange on whether to support the WUR operation in a link setup procedure. In more detail, the wireless communication terminal may transmit a WUR capability element to the base wireless communication terminal through a probe request frame, an authentication request frame, and an association request frame. The WUR capability element is an element indicating the capability that the wireless communication terminal supports in connection with the WUR operation. In addition, the wireless communication terminal may transmit a WUR capability element to the base wireless communication terminal using a separate action frame. Also, the base wireless communication terminal and the wireless communication terminal may transmit a WUR mode element including information on a WUR operation related parameter in a link establishment procedure. Also, the base wireless communication terminal and the wireless communication terminal may transmit the WUR mode element through an action frame. The WUR mode element will be described in detail with reference to FIG. 11.

The wireless communication terminal may perform a WUR related operation after connecting with the base wireless communication terminal. When the wireless communication terminal intends to enter the PCR dose state, the wireless communication terminal may transmit a WUR action frame to the base wireless communication terminal. WUR action frames are exchanged for the wireless communication terminal and the base wireless communication terminal to set parameters related to the WUR operation. WUR action frames can be exchanged via PCR. In addition, the WUR action frame may request an ACK from the receiver of the WUR action frame. When the base wireless communication terminal that receives the WUR action frame determines that a change or confirmation of a parameter related to the WUR operation is necessary, the base wireless communication terminal may transmit an additional WUR action frame to the base wireless communication terminal. The parameter related to the WUR operation may include at least one of a WUR duty-cycle period and a length of on duration. The exchange process of the WUR action frame may be repeated until the setting of parameters related to the WUR operation is completed. When the parameter agreement related to the WUR operation is completed, the wireless communication terminal may change the power management mode to the power save mode and enter the PCR dose state.

A WUR station ID (WUR station ID) for identifying a corresponding wireless communication terminal by a wireless communication terminal in a PCR dose state or a WUR group ID for identifying a plurality of wireless communication terminals including the corresponding wireless communication terminal. When receiving the wake-up frame indicating), the wireless communication terminal stores the information indicated by the wake-up and turns on the PCR transceiver. Specifically, the wireless communication terminal stores the information indicated by the wake-up and transmits a signal for turning on the PCR transceiver. When the PCR transceiver is turned on, the wireless communication terminal may transmit information obtained from the wake-up frame to the PCR transceiver. In this case, the information obtained from the wake-up frame may include at least one of the above-described packet number and TSF (Timer Synchronization Function).

After the PCR transceiver is turned on, the wireless communication terminal can transmit an awake indication to the base wireless communication terminal. In this case, the awake frame may indicate a frame first transmitted by the wireless communication terminal to the base wireless communication terminal through the PCR transceiver after the wake-up of the PCR transceiver. The awake frame may be a frame indicating that the PCR transceiver of the wireless communication terminal transmitting the awake frame is in an awake state. This is because the base wireless communication terminal needs to confirm whether the wireless communication terminal has woken up successfully.

In more detail, when a WUR PPDU is transmitted through a WUR, one bit is transmitted through one OFDM symbol. Therefore, the transmission time of the WUR PPDU through the WUR is very long. In addition, a PCR transition delay, which is a time required to turn on a PCR transceiver in a PCR dose state, may also be a relatively long time. Therefore, even if the wireless communication terminal fails to wake up, if the base wireless communication terminal attempts to transmit through PCR, it is necessary to perform the wake-up process again and it may take a relatively long time before the wireless communication terminal wakes up. There is no choice but to. The wireless communication terminal may reduce the time required for awake frame transmission by transmitting an awake frame using a PCR rather than a WUR. The wireless communication terminal may transmit an awake frame according to a channel access method for PCR.

The awake frame may be a separate control frame defined for the WUR operation. In addition, the awake frame may be a frame used in an existing WLAN standard such as a PS-poll frame. If the base wireless communication terminal wants to receive an awake frame after designating a specific time, the wireless communication terminal may attempt channel access for awake frame transmission after a corresponding time elapses after the wake-up. In this case, the wireless communication terminal may obtain information about a specific time through the WUR capability element. The WUR capability element may be transmitted through a probe request frame, an authentication request frame, and a connection request frame as described above. In addition, the wireless communication terminal may obtain information about a specific time through the WUR action frame.

The base wireless communication terminal receiving the awake frame may transmit an awake response frame (hereinafter referred to as an "AW response frame") to the wireless communication terminal. The AW response frame may be an immediate response frame. In more detail, the AW response frame may be an ACK frame. In addition, the AW response frame may be a control frame separately defined for the WUR operation. In addition, the AW response frame may be QoS data. The wireless communication terminal receiving the AW response frame may perform a general PCR operation.

When the base wireless communication terminal does not receive the awake frame until a predetermined time from the time when the base wireless communication terminal transmits the wake-up frame, the base wireless communication terminal may determine that the wake-up of the wireless communication terminal has failed. At this time, the base wireless communication terminal may transmit the wake-up frame again to the wireless communication terminal. In order to determine whether a predetermined time has elapsed, the base wireless communication terminal may set a timer after transmitting the wake-up frame. The predetermined time may be a time longer than the sum of the PCR switching delay and the NAVSyncDelay value of the wireless communication terminal. NAVSyncDelay represents a time at which the transmission of the wireless communication terminal is prohibited so that the wireless communication terminal can set the NAV based on a frame or PPDU transmitted through PCR after the wake-up.

In an embodiment of FIG. 8, a first WUR station (WUR STA1) and a second WUR station (WUR STA2), which are APs, perform a link establishment procedure. At this time, the first WUR station WUR STA1 and the second WUR station WUR STA2 exchange the WUR capability element with the WUR mode element. In addition, the second WUR station (WUR STA2) transmits a WUR action frame to the first WUR station (WUR STA1) to enter the WURX dose state. The first WUR station WUR STA1 and the second WUR station WUR STA2 exchange action frames to set parameters related to the WUR operation. When there is data to be transmitted to the first WUR station (WUR STA1) to the second WUR station (WUR STA2), the first WUR station (WUR STA1) transmits a wake-up frame to the second WUR station (WUR STA2). The second WUR station (WUR STA2) receives the wake-up frame and turns on the PCR transceiver. At this time, it takes time as much as the PCR switching delay until the PCR transceiver is turned on. After the PCR transceiver is turned on, the second WUR station (WUR STA2) transmits an awake frame to the first WUR station (WUR STA1). The first WUR station WUR STA1 transmits an AW response frame to the second WUR station WUR STA2. These operations allow the wireless communication terminal to enter the PCR dose state and wake up again.

Hereinafter, the format of the WUR capability element described with reference to FIG. 8 will be described in detail with reference to FIG. 9. 9 illustrates a configuration of a WUR capability element according to an embodiment of the present invention. The WUR capability element may follow the format of a general extension element of the 802.11 standard. In more detail, the WUR capability element may include an Element ID field, a Length field, and an Element ID extention field. In addition, the WUR capability element may include information indicating a frequency band in which the wireless communication terminal transmitting the WUR capability element can transmit and receive a WUR frame. In more detail, the WUR capability element may include a Supported Bands field. The Supported Bands field may include bits corresponding to each of the plurality of frequency bands. For example, the Supported Bands field may include at least one bit indicating whether WUR frame transmission / reception is possible through the first frequency band. In addition, the Supported Bands field may include at least one bit indicating whether WUR frame transmission / reception is possible through the second frequency band. In this case, the first frequency band and the second frequency band may be different from each other. In addition, the plurality of frequency bands may include frequency bands of 2.4 GHz and 5 GHz. In addition, when the terminal transmitting the Supported Bands field is a base wireless communication terminal, the Supported Bands field may be used as a reserved field.

In addition, the WUR capability element may further include WUR Capability information. For example, the WUR capability element may include PCR conversion delay information which is a time required for the wireless communication terminal transmitting the WUR capability element to turn on the PCR transceiver in the PCR dose state. The base wireless communication terminal transmitting the wake-up frame may determine whether the wake-up has failed based on a time longer than the sum of the PCR switching delay and the time required to transmit the awake frame. After transmitting the wake-up frame, the base wireless communication terminal may set a timer having a period longer than the sum of the time required for transmitting the PCR switching delay and the awake frame. When the timer expires, the base wireless communication terminal may determine that the wake-up has failed.

The WUR capability element may include a NAVSyncDelay field. The NAVSyncDelay field may include individual NAVSyncDelays of the wireless communication terminal described above with reference to FIG. 8. According to another embodiment, the NAVSyncDelay may be included in one field together with the above-described PCR conversion delay information. For example, the WUR capability element may include a field indicating a value obtained by adding NAVSyncDelay to a PCR conversion delay.

The WUR capability element may include information indicating whether a wireless communication terminal that has transmitted the WUR capability element can receive a WUR frame having a variable length. In more detail, the WUR capability element may include a VL WUR Frame Support field. When the VL WUR Frame Support field is activated, the wireless communication terminal may receive a WUR frame having a variable length. In contrast, when the VL WUR Frame Support field is deactivated, the wireless communication terminal can receive only fixed length WUR frames transmitted with a preset length without the Frame Body field. In this case, the fixed length WUR frame may be referred to as a minimum length (ML) wake-up frame.

The WUR Capability element may include a WUR Group IDs Support field. The WUR Group IDs Support field may indicate whether the wireless communication terminal that sent the WUR capability element can receive a WUR frame identified by the group ID. The base wireless communication terminal may transmit a WUR frame identifying the receiver with a unique WUR STA ID to the wireless communication terminal signaling that it cannot receive a WUR frame identifying the receiver by the group ID through the WUR Group IDs Support field. have. The base wireless communication terminal cannot transmit the WUR frame identifying the receiver by the WUR group ID to the wireless communication terminal signaling that the WUR frame identifying the receiver by the WUR group ID is not available through the WUR Group IDs Support field.

In addition, the WUR Group IDs Support field may indicate the maximum number of WUR group IDs that can be processed by the wireless communication terminal that has transmitted the WUR capability element. The base wireless communication terminal may allocate a WUR group ID having a maximum number less than or equal to the maximum number signaled by the corresponding wireless communication terminal through the group-address WUR frame information to the wireless communication terminal that has transmitted the WUR capability element. Also, the base wireless communication terminal cannot assign a WUR group ID exceeding the maximum number signaled by the corresponding wireless communication terminal through the group-address WUR frame information to the wireless communication terminal that has transmitted the WUR capability element. In this case, the size of the group ID bitmap may be determined based on the maximum number of WUR group IDs that the wireless communication terminal can process. The base wireless communication terminal may transmit a WUR group ID assigned to a specific wireless communication terminal using the group ID bitmap. In addition, the wireless communication terminal may obtain a WUR STA ID of the wireless communication terminal based on the size of the group ID bitmap. In this case, the base wireless communication terminal may not separately transmit the WUR STA ID of the wireless communication terminal.

The WUR capability element may include information indicating whether the wireless communication terminal that transmits the WUR capability element supports MIC (Message Integrity Check) operation. This information may be referred to as a Protected WUR Frame Support field. The base wireless communication terminal may transmit a WUR frame using MIC instead of FCS to the wireless communication terminal signaling that it supports MIC operation through the Protected WUR Frame Support field. The base wireless communication terminal may not be allowed to transmit the WUR frame using the MIC instead of the FCS to the wireless communication terminal signaling that the MIC operation is not supported through the Protected WUR Frame Support field. The wireless communication terminal supporting the MIC may detect an external attack through the MIC operation. In this case, the wireless communication terminal may transmit an action frame for requesting a new WUR STA ID to the base wireless communication terminal.

Hereinafter, the WUR operation element including parameters related to the WUR operation of the wireless communication terminal will be described with reference to FIG. 10. 10 illustrates a configuration of a WUR operation element according to an embodiment of the present invention. The WUR operation element may include a parameter related to a WUR operation that the base wireless communication terminal is operating in the BSS. Parameters signaled via the WUR operation element may be commonly applied to wireless communication terminals operating in the WUR mode. In addition, parameters individually applied to each wireless communication terminal may be set through a WUR mode element to be described later.

The WUR operation element may follow the form of a general extension element of the 802.11 standard. In more detail, the WUR capability element may include an Element ID field, a Length field, and an Element ID extention field. In addition, the WUR operation element may include a WUR operation parameter composed of the WUR duty-cycle operation and related parameters.

The WUR operation element may include information indicating a minimum awake holding time of the wireless communication terminal in on-duration during WUR duty-cycle operation. This information may be referred to as minimum wake-up duration information. In this case, the minimum awake holding time may be indicated in units of 256 microseconds. The WUR operation element may include information indicating a unit for indicating a period of the WUR duty cycle. This information may be referred to as WUR duty-cycle period units information.

The WUR operation element may include information indicating at least one channel that the base wireless communication terminal can use to transmit the WUR frame. This information may be referred to as WUR operating class information. The WUR operation element may include information indicating a channel being used for WUR frame transmission among at least one available channel. This information may be referred to as WUR channel information.

The WUR operation element may include information related to a WUR beacon frame reception period. In detail, the WUR offset element may include information indicating the number of time units between consecutive target WUR beacon transmission times (TWBTTs). In addition, the WUR offset element may include information indicating a target WUR beacon transmission time that arrives earlier based on the current time. In addition, the WUR operation element may include an additional WUR parameter field. For example, the WUR parameter field may include a PCR BSS parameter update counter value that the base wireless communication terminal inserts into the WUR beacon frame and transmits.

The WUR operation element may include a WUR Connectivity Timeout field. The WUR Connectivity Timeout field may indicate the maximum time that the wireless communication terminal can maintain the WUR mode without exchanging a frame through PCR with the base wireless communication terminal. In the WUR mode, the wireless communication terminal can operate in a PCR dose state. For example, the wireless communication terminal operating in the WUR mode may maintain the PCR dose state except at the time of receiving a wake-up frame from the base wireless communication terminal or attempting uplink transmission. The wireless communication terminal according to an embodiment of the present invention may set a timer for maintaining the PCR dose state without exchanging PCR frames with the base wireless communication terminal. This is because when the wireless communication terminal maintains the PCR dose for a long time, it may be difficult to identify whether the base wireless communication terminal is out of the BSS corresponding to the base wireless communication terminal.

If the base radio communication terminal does not exchange the PCR frame with the radio communication terminal until the timer indicated by the WUR Connectivity Timeout field expires, the base radio communication terminal is lost connectivity with the radio communication terminal. You can judge. In addition, when the base wireless communication terminal does not receive a PCR frame from the wireless communication terminal until the timer expires, the base wireless communication terminal may discard the association-related information with the wireless communication terminal. In detail, the base wireless communication terminal may transmit a wake-up frame to the wireless communication terminal. Next, the base wireless communication terminal may transmit a disassociation request frame for requesting disassociation through PCR to the wireless communication terminal. Alternatively, the base wireless communication terminal may suspend transmission of the disassociation request frame until the time for the timer for determining transmission failure of the transmitted wake-up frame expires. In this case, when there is no response from the wireless communication terminal until the timer for determining the failure of transmission of the wake-up frame expires, the base wireless communication terminal may discard the association related information with the wireless communication terminal. Alternatively, when the timer indicated by the WUR Connectivity Timeout field expires, the base wireless communication terminal may immediately release the association with the wireless communication terminal.

According to an embodiment, when the wireless communication terminal needs continuous connection with the base wireless communication terminal, the wireless communication terminal may attempt to transmit the PCR frame before the timer indicated by the WUR Connectivity Timeout field expires. If the wireless communication terminal does not transmit the frame before the timer expires, the wireless communication terminal may determine that the connection with the base wireless communication terminal is disconnected. The timer indicated by the WUR Connectivity Timeout field may be updated when successful PCR frame exchange is completed between the wireless communication terminal and the base wireless communication terminal. In addition, when the wireless communication terminal enters the WUR mode, the timer indicated by the WUR Connectivity Timeout field may be set from the time when the wireless communication terminal transmits an acknowledgment frame (Ack) to the action frame for approving the wireless communication terminal to enter the WUR mode. Can be.

Hereinafter, a WUR action frame transmitted by a wireless communication terminal for setting a parameter related to a WUR operation will be described with reference to FIG. 11. The WUR mode element used for setting the parameters related to the WUR operation will also be described. 11 shows an example configuration of a WUR action frame and an example configuration of a WUR mode element.

According to an embodiment of the present invention, the wireless communication terminal may set a parameter related to the WUR operation by transmitting a WUR mode element to the base wireless communication terminal. As described above, the wireless communication terminal can transmit the WUR mode element in the link setup process. In addition, the wireless communication terminal may transmit the WUR mode element through the action frame.

11 (a) shows the format of a WUR action frame according to an embodiment of the present invention. The format of the WUR action frame may follow the general action frame format of the 802.11 standard. In this case, the Category field of the WUR action frame may be set to WUR. In addition, the WUR action frame may include a Dialog Token field and a WUR mode element field. The Dialog Token value may indicate a transmission order of sequentially transmitted WUR action frames. The WUR mode element may include a parameter related to the operation of the wireless communication terminal in the WUR mode. For example, the wireless communication terminal can transmit a WUR mode element through a WUR action frame.

11 (b) shows an exemplary format of a WUR mode element according to an embodiment of the present invention. The WUR mode element may include information indicating a role of the WUR action frame in the WUR action frame. Information representing the role of the WUR action frame may be signaled through the Action Type field. The wireless communication terminal and the base wireless communication terminal that exchanged the WUR action frame may perform an operation according to the Action Type field of the exchanged WUR action frame. The Action Type field may indicate any one of Enter WUR Mode Request / Response, Enter WUR Mode Suspend Request / Response, Enter WUR Mode Suspend, and Enter WUR Mode for each action.

The WUR mode element may include information indicating a response to the values included in the first received WUR mode element. The corresponding information may be signaled through the WUR Mode Response Status field. In this case, the wireless communication terminal that transmitted the first WUR mode element may be referred to as a requesting terminal. Also, a wireless communication terminal that receives a first WUR mode element from a requesting terminal and transmits a new second WUR mode element in response to the first WUR mode element may be referred to as a responding terminal. In this case, the requesting terminal may be any one of an AP and a non-AP station. Similarly, the responding terminal may be either an AP or a non-AP station. The WUR Mode Response Status field may be set to Accept or Denied.

 The WUR mode element may include information indicating the configuration of subsequent WUR parameters. This information may be referred to as WUR paramerters Control. For example, the WUR paramerters Control field may include a Group ID List Present field indicating that a wireless communication terminal that has transmitted a WUR mode element has a WUR group ID assignment. According to an embodiment, when the Group ID List Present is activated, the subsequent WUR parameter field may include a Group ID List field indicating a WUR group ID assigned to the wireless communication terminal.

The WUR mode element may include WUR mode related parameters indicated in the WUR paramerters Control field. For example, the WUR mode element may include information indicating a WUR identifier assigned to the wireless communication terminal. In addition, the WUR mode element may include information indicating a parameter related to the WUR duty-cycle operation of the wireless communication terminal. For example, the parameter related to the WUR duty-cycle operation may include a TSF value indicating the start time of the WUR duty-cycle of the wireless communication terminal.

As described above, when the Group ID List Present is activated in the WUR Parameters Control field, the WUR mode element may include information indicating a WUR group ID assigned to the wireless communication terminal. Information indicating the WUR group ID allocated to the wireless communication terminal may be signaled in the form of a bitmap. The WUR mode element may include a group ID bitmap field. For example, the WUR mode element may include a Group ID Bitmap Size field indicating the size of the group ID bitmap. In this case, the size of the group ID bitmap including the WUR group ID information may be smaller than the maximum number of group IDs that the wireless communication terminal can process. The maximum WUR group ID may be signaled through the aforementioned WUR capability element.

In addition, the WUR mode element may include a Starting Group ID (SGID) field indicating a range of a position corresponding to the WUR group ID in the bitmap. The wireless communication terminal may obtain a WUR group ID assigned to the group including the wireless communication terminal based on the Group ID Bitmap Size field value and the Starting Group ID value. The wireless communication terminal may obtain WUR group ID allocation information by a combination of an SGID value and an Ending Group ID (EGID) value. Here, the EGID may be calculated based on the signaled group ID bitmap size value and the SGID value. According to an embodiment, when the value of the nth bit in the group ID bitmap is 1 and SGID + n is less than or equal to EGID, it may indicate that a WUR group ID corresponding to SGID + n is allocated to the terminal. On the contrary, when the value of SGID + n is greater than the EGID, it may indicate that a WUR group ID corresponding to SGID + n-64 is allocated to the terminal. In the WUR BSS, the WUR group ID may be any one of 64 consecutive values among 12-bit values. In this case, one or more wireless communication terminals included in the WUR BSS may be terminals operating in the WUR mode. Therefore, the size of the group ID bitmap included in the WUR mode element can be minimized through the above-described method.

According to a further embodiment, the base wireless communication terminal may allocate the WUR group ID and the WUR STA ID with consecutive values based on the TXID in order to minimize the WUR STA ID storage space and the WUR STA ID allocation complexity. When the TXID value determined based on the PCR BSSID is close to the 0xFFF value, it may be difficult to obtain 64 consecutive values based on the TXID. In this case, a separate rule for allocating the WUR group ID and the WUR STA ID may be required according to the location of the TXID value. According to an embodiment, the base wireless communication terminal may utilize a modulo operation of 2 ^ 12 units for WUR group ID allocation. For example, if the nth value of the group ID bitmap is 1 and (SGID + n)% (2 ^ 12) is less than or equal to EGID% (2 ^ 12), then (SGID + n)% (2 ^ It may indicate that the WUR group ID corresponding to 12) has been allocated to the terminal. Conversely, if the value of (SGID + n)% (2 ^ 12) is greater than EGID% (2 ^ 12), the WUR group ID corresponding to (SGID + n-64)% (2 ^ 12) is assigned to the terminal. Can be indicated. Through this, the base wireless communication terminal may allocate the WUR group ID and the WUR STA ID to the wireless communication terminals with the same rule regardless of the TXID value of the BSS.

12 illustrates a format of a WUR PPDU (PCLP Protocol Data Unit) according to an embodiment of the present invention. The WUR PPDU may include a legacy part that the PCR transceiver can demodulate. In detail, the WUR PPDU may be divided into a legacy part that the PCR transceiver can demodulate and a wake-up part that the PCR transceiver cannot demodulate. As described above, the BSS may simultaneously include a wireless communication terminal supporting WUR-based power save and a legacy wireless communication terminal not supporting WUR-based power save. In this case, the operation of the wireless communication terminal supporting the WUR-based power save needs not to interfere with the operation of the legacy wireless communication terminal present in the BSS.

Specifically, the legacy part may include a legacy preamble (L-Preamble) used in the existing 802.11 standard. In more detail, the legacy preamble may include an L-STF including a short training signal, an L-LTF including a long training signal, and an L-SIG including signaling information for a legacy wireless communication terminal. The legacy wireless communication terminal can determine the length of the WUR PPDU using the legacy preamble. Accordingly, the legacy wireless communication terminal may not access the frequency band in which the WUR PPDU is transmitted while the WUR PPDU is being transmitted. Through this, it is possible to prevent the legacy wireless communication terminal from interfering with the signal including the WUR part following the legacy part.

In addition, the WUR PPDU may include a WUR symbol. For example, the WUR symbol may be one OFDM symbol following the L-SIG. The WUR symbol may be an OFDM symbol modulated in a binary phase shift keing (BPSK) scheme. In addition, the WUR symbol may include information indicating a transmission type of the WUR part. For example, the transmission type may be any one of unicast, multicast, and broadcast. If the transmission type is unicast, the WUR part to be described later may include identification information indicating a wireless communication terminal to be a wake-up target. In this case, the identification information may be an association identifier (AID) used in PCR. Alternatively, the identification information may be a WUR identifier (WUR ID) used in the WUR. In the present disclosure, the WUR identifier may be an identifier for identifying an intended recipient of a frame transmitted and received through a waveform used in the WUR.

The wireless communication terminal supporting the WUR-based power save may demodulate the WUR part through the WURx. At this time, the WUR part may be divided into WUR SYNC and WUR DATA. The WUR SYNC may include a signal pattern sequence representing a WUR PPDU. In detail, the base wireless communication terminal may insert a pseudo noise sequence based on WURx modulation into the WUR SYNC. The base wireless communication terminal may insert a pseudo noise sequence using the OOK in the WUR SYNC. The signal pattern sequence may be a pattern applied equally regardless of the wireless communication terminal receiving the WUR PPDU. The wireless communication terminal supporting the WUR-based power save may check whether the received signal is a WUR PPDU through the signal pattern sequence. In addition, the wireless communication terminal may determine whether the WUR PPDU is a high data rate (HDR) or a low data rate (LDR) through a signal pattern sequence.

WUR DATA represents a WUR frame, which is a MAC frame included in a WUR PPDU. WUR DATA may be divided into a MAC header, a frame body field, and a frame check sequence (FCS) field. The wireless communication terminal supporting the WUR-based power save may determine the receiver of the received WUR PPDU by parsing the WUR DATA of the WUR PPDU. For example, the MAC header may include an ID field indicating a receiver of the WUR PPDU. In addition, the frame body field may include information of variable length according to the type of the WUR PPDU. Hereinafter, the WUR DATA of the WUR frame will be described in detail with reference to FIG. 13.

13 illustrates a specific format of a WUR frame according to an embodiment of the present invention. The MAC header of the WUR DATA described with reference to FIG. 12 may be divided into a frame control field, an ID field, and a type dependent control field. In this case, the Frame Control field represents basic control information about the WUR frame. In addition, the ID field may indicate information about an address of a sender or a receiver of a WUR frame. In more detail, the ID field may include at least one of information representing an address of a sender of a WUR frame and information representing an address of a receiver. In addition, the Type Dependent Control field represents variable control information changed according to the type of the WUR frame.

According to an embodiment, the Frame Control field may include a Type field. The Type field may indicate the frame type of the corresponding WUR frame. In detail, the Type field may indicate whether the WUR frame is a WUR beacon frame, a wake-up frame, a WUR discovery frame for discovering a BSS using WUR, or a vendor specific frame.

In addition, the Frame Control field may include a Protected field. The Protected field may indicate whether the WUR frame is a frame protected by additional encryption. For example, the Protected field may indicate whether the frame requires verification by Message Intergrity Check (MIC). The protected field may be a 1-bit field. If the Protected field indicates that the MIC is required, the wireless communication terminal receiving the WUR frame may check whether the WUR frame is valid using the MIC. When the wireless communication terminal determines that the WUR frame is valid through the MIC, the wireless communication terminal may include a value calculated by the MIC rather than a value calculated by the CRC. If the wireless communication terminal determines that the WUR frame is not valid through the MIC, the wireless communication terminal may discard the WUR frame. In more detail, when frame validation is required through MIC, the FCS field of the WUR frame may indicate a message integrity value. The wireless communication terminal receiving the WUR frame may perform the MIC using the encryption key received in advance.

In addition, the Frame Control field may include a Length Present field. The Length Present field may indicate whether the corresponding WUR frame includes a Frame Body field. If the Length Present field of the WUR frame indicates that the WUR frame does not include the Frame Body field, the WUR frame may be a fixed length frame. When the Length Present field of the WUR frame indicates that the WUR frame includes a Frame Body field, the WUR frame may be a variable length frame.

In addition, the Frame Control field may include a Length / Misc field. The Length / Misc field may indicate the length of the WUR frame or additional information other than the length of the WUR frame according to whether the WUR frame corresponds to a variable length WUR frame format. In detail, when the WUR frame corresponds to a WUR frame format having a variable length, the Length / Misc field may indicate information about the length of the WUR frame. The information about the length of the WUR frame may indicate at least one of the length of the WUR frame or the length of the Frame body field. According to an embodiment, when the WUR frame corresponds to a WUR frame format having a variable length, the Length / Misc field may indicate a length within a preset range of bits. When the Length / Misc field uses 3-bits, the Length / Misc field may indicate the length of the frame body field of 2 to 16 octets in units of 2 octets. According to another embodiment, the length of the WUR frame may be indicated by a method of indicating the number of preset unit information included in the frame body field. For example, the Frame Body field may include an additional WUR identifier (eg, WUR STA ID or WUR group ID) in addition to the identifier included in the ID field. In this case, the Length / Misc field may indicate the number of individual identifiers included in the frame body. When the WUR frame corresponds to a fixed length WUR frame format, the Length / Misc field may include predefined additional information. The order in the above-described protected field, the length present field, and the MAC header of the Length / Misc field may be changed according to implementation.

The ID field may include a WUR identifier indicating the intended recipient of the WUR frame. For example, the ID field may indicate either the ID of the sender or the ID of the receiver. The ID field of the WUR frame may not distinguish the ID of the sender or the ID of the receiver. In more detail, the WUR frame may not include information indicating whether the WUR identifier indicated by the ID field is an identifier of a sender or an identifier of a receiver. For example, the ID field of the WUR frame may indicate one of a transmitter ID (TX), a WUR STA ID, and a WUR group ID. In this case, each of the TXID, the WUR STA ID, and the WUR group ID may be a value determined within a single WUR identifier space to be described later.

The wireless communication terminal may determine whether the wireless communication terminal is an intended receiver of the WUR frame based on the ID field of the WUR frame. In addition, if the wireless communication terminal is the intended recipient of the received WUR frame, the wireless communication terminal may perform subsequent operations in accordance with the received WUR frame. In this case, a method of determining the WUR identifiers inserted into the ID field and a method of interpreting the ID field by the wireless communication terminal will be described in detail with reference to FIGS. 14 to 18.

According to an embodiment, the type of the identifier included in the ID field may vary according to the role of the WUR frame. For example, if the WUR frame indicates an individual wake-up of a single wireless communication terminal, the ID field of the WUR frame may include a WUR STA ID identifying a specific wireless communication terminal. In detail, when the wireless communication terminal receives a wake-up frame including a WUR STA ID indicating the wireless communication terminal, the wireless communication terminal may wake up the PCR transceiver. The base wireless communication terminal may assign different WUR STA IDs (WUR STA IDs) identifying each of the plurality of wireless communication terminals to each of the plurality of wireless communication terminals coupled with the base wireless communication terminal.

In addition, when the WUR frame is a WUR beacon frame, the ID field may include a transmitter ID (Transmitter ID, TXID) identifying the base wireless communication terminal. When the WUR frame is a wake-up frame broadcast to a specific BSS, the ID field may include a specific WUR identifier that identifies the BSS. When the WUR frame is a wake-up frame for wake-up of a plurality of wireless communication terminals corresponding to a specific group, the ID field may indicate a WUR group ID.

According to an embodiment, when the WUR frame is a variable length frame format, the Frame Body field of the WUR frame may include at least one WUR STA ID. In this case, the ID field may include a WUR identifier corresponding to any one of a group to which the WUR identifiers included in the Frame Body field commonly belong, a BSS and a TXID to which the WUR identifiers commonly belong.

The Type Dependent Control field (TD field) may include a Counter field and a Sequence number field. In a specific embodiment, the Counter field may indicate whether the BSS related parameter is updated. For example, the Counter field may include BSS update counter information. When the wireless communication terminal receives a counter field indicating a counter value different from a counter value previously received, the wireless communication terminal may trigger the reception of a PCR beacon. In addition, the sequence number field may include information on a partial timing synchronization function (partial TSF) for time synchronization between the base wireless communication terminal and the wireless communication terminal.

In addition, the configuration of the TD field may vary depending on a protection method of the WUR frame. For example, when the aforementioned Protected field of the WUR frame is activated, the TD field may be configured differently depending on whether a common IPN scheme is used to detect a replay attack. For example, when using the common IPN scheme, the Counter field is used as a reserved field, and the Sequence number field may include 8-bits of a specific position among bits representing the TSF. On the other hand, when the common IPN method is not used, the TD field may include a Counter field including 4-bit and a Sequence number field including 8-bit among 12-bit PPNs. In this case, the PPN may represent 12-bits of a specific position among the bits representing the TSF.

When the WUR frame corresponds to a variable length WUR frame format, the length of the Frame Body field may be variable. In this case, the Type field may represent that the length of the WUR frame is variable. In addition, the subtype field indicating the subtype of the WUR frame may indicate the length of the Frame Body field. In more detail, the subtype field may indicate the length of a WUR frame based on a predetermined information unit instead of a bit unit. For example, the frame body field may include a plurality of subfields indicating information about each of the plurality of WUR wireless communication terminals. In more detail, the Frame Body field may include a first subfield indicating information about a first WUR wireless communication terminal and a second subfield indicating information about a second WUR wireless communication terminal. In addition, one subfield may indicate information about a plurality of WUR STA IDs corresponding to the WUR group ID. When the frame body field includes a plurality of subfields indicating information about each of a plurality of WUR wireless communication terminals, the subtype field may indicate information about the length of the frame body field using the number of subfields. . For example, when the frame body field includes subfields for each of two WUR STA IDs, the subtype field may indicate that the number of subfields included in the frame body field is two. When the WUR frame is a WUR beacon frame and corresponds to a variable length WUR frame format, the Frame Body field may include information about management. In this case, the length of the frame body field may be indicated based on a predetermined information unit as described above. If the WUR frame corresponds to a fixed length WUR frame format, the WUR frame may not include a Frame body field.

The WUR frame may include an FCS field indicating a value used to validate the WUR frame. The wireless communication terminal receiving the WUR frame may determine whether an error is included in the transmission and reception of the WUR frame based on the values of the fields included in the WUR frame and the value of the FCS field. Specifically, the wireless communication terminal receiving the WUR frame generates a FCS value by performing a CRC operation based on the values of the fields included in the WUR frame, and compares the generated FCS value with the value of the FCS field. When the generated FCS value and the value of the FCS field are the same, the wireless communication terminal may determine that no error occurs during the transmission and / or reception of the WUR frame. If the generated FCS value and the value of the FCS field are different, the wireless communication terminal may determine that an error has occurred during the transmission and / or reception of the WUR frame. The WUR frame may not include an identifier of the base wireless communication terminal. In addition, the WUR frame may be transmitted without being encrypted. Therefore, the external wireless communication device can copy and retransmit the field value of the WUR frame. Through this, the external wireless communication device can induce power consumption by causing the wireless communication terminal to wake up unnecessarily. In order to prevent this, the following embodiment may be applied to a wireless communication terminal and a base wireless communication terminal.

In a specific embodiment, the wireless communication terminal receiving the WUR frame may generate an FCS value by performing a CRC operation considering not only the values of the fields included in the WUR frame but also the values of the virtual fields not included in the WUR frame. The wireless communication terminal can compare the value of the generated FCS and the value of the FCS field. Accordingly, the base wireless communication terminal may set the value of the FCS field by performing a CRC operation in consideration of not only the values of the fields included in the WUR frame but also the values of the virtual fields not included in the WUR frame. In this case, the value of the virtual field may be a value negotiated in advance between the base wireless communication terminal and the wireless communication terminal. In addition, when there is no Frame Body field of the WUR frame, when generating the FCS value, the wireless communication terminal and the base wireless communication terminal may regard the virtual field as located behind the MAC header. In addition, when there is a Frame Body field of the WUR frame, when generating the FCS value, the wireless communication terminal and the base wireless communication terminal may regard the virtual field as located behind the Frame Body field.

The virtual field may be referred to as an embedded BSSID field. The wireless communication terminal may compare the generated FCS value with the value of the received FCS field to determine whether the embedded BSSID matches. That is, the wireless communication terminal can determine whether the embedded BSSID identifies the base wireless communication terminal combined with the wireless communication terminal by comparing the generated FCS value with the value of the received FCS field. Even if there is no error in the transmission and reception of the WUR frame, the FCS value may be different if the embedded BSSID used in generating the FCS and the embedded BSSID used in generating the value of the received FCS field do not match. Because there is.

For example, the first base wireless communication terminal may insert an FCS value based on the BSSID of the first base wireless communication terminal into the WUR frame. In addition, the wireless communication terminal may generate the FCS value using the BSSID of the second base wireless communication terminal combined with the wireless communication terminal. In this case, when the first base wireless communication terminal and the second base wireless communication terminal are different, the FCS generated by the wireless communication terminal may not match the FCS value of the WUR frame. Through this operation, the wireless communication terminal can determine not only whether the WUR frame includes an error but also whether the corresponding WUR frame is a WUR frame transmitted from a base wireless communication terminal associated with the wireless communication terminal.

14 illustrates a WUR identifier space according to an embodiment of the present invention. According to an embodiment, the WUR identifiers inserted into the ID field and / or frame body field of the WUR frame may be a value determined within a single WUR identifier space. For example, the WUR identifier may include at least one of a TXID, a WUR STA ID, or a WUR group ID. When the base wireless communication terminal uses multiple Basic Service Set Identifier (BSSID) sets, the WUR identifier may include at least one of a TXID, a WUR STA ID, a WUR group ID, or a nontransmitter ID (NTXID). In the present disclosure, the multiple BSSID set may refer to a BSSID set including a BSSID of each of a plurality of BSSs operated by one base wireless communication terminal. In more detail, the multiple BSSID set may refer to a BSSID set including BSSIDs of each of a plurality of BSSs sharing an operating channel. In addition, the multiple BSSID set may refer to a BSSID set including BSSIDs of each of a plurality of BSSs sharing a probe response frame or a beacon frame. TXID, NTXID, WUR STA ID and WUR group ID may be determined based on one WUR identifier space. In addition, WUR identifiers that distinguish each of unicast, groupcast, and broadcast in the BSS may be determined to have different values. Within the same BSS, where duplicate values are used for more than one WUR identifier, it may be difficult for the wireless communication terminal to determine if the wireless communication terminal is the intended recipient of the WUR frame. This is because the ID field of the WUR frame does not distinguish between the sender ID and the receiver ID. This is because the WUR frame does not include a separate field into which the WUR group ID is inserted. In this case, the WUR identifier space may indicate an area of values that can be expressed using a predetermined number of bits. According to an embodiment, the preset number of bits may be 12-bits. For example, the TXID may be any of the values representable using 12-bit.

According to an embodiment, the WUR identifier for identifying the BSS may be either TXID or at least one NTXID according to the BSSID corresponding to the BSS. When the base wireless communication terminal uses multiple BSSID sets, the base wireless communication terminal may communicate with the plurality of wireless communication terminals using the plurality of BSSs. In this case, when the BSSID of the first BSS is a transmitted BSSID transmitted from the base wireless communication terminal to the wireless communication terminal, the WUR identifier for identifying the first BSS may be TXID. In addition, when the BSSID of the second BSS different from the first BSS and operated by the base wireless communication terminal is not the BSSID transmitted from the base wireless communication terminal to the wireless communication terminal, the WUR identifier for identifying the second BSS may be NTXID. have. In this case, the BSSID of the second BSS may be referred to as an untransmitted BSSID. For example, multiple BSSID sets may consist of one transmitted BSSID and at least one untransmitted BSSID.

The base wireless communication terminal may determine a WUR identifier for identifying each of the base wireless communication terminal, the BSS, and the wireless communication terminal communicating with the base wireless communication terminal based on the WUR identifier space. The base wireless communication terminal may determine a TXID identifying the base wireless communication terminal in the WUR identifier space. For example, the base wireless communication terminal may select an arbitrary value among the representable values using 12-bit and use the selected value as the TXID. In addition, according to an embodiment, the base wireless communication terminal may determine a WUR identifier for identifying the BSS in the WUR identifier space. In detail, when the base wireless communication terminal operates multiple BSSIDs, the base wireless communication terminal may determine an NTXID for identifying a specific BSS in the WUR identifier space.

On the other hand, the WUR identifier used in wireless communication via WUR is not a device-specific identifier. Therefore, the identifier indicating the BSS to which the wireless communication terminal belongs may be the same as the identifier identifying the adjacent overlapping BSS (OBSS). In addition, the same WUR identifier may be used between wireless communication terminals belonging to each of adjacent different BSSs. According to an embodiment, the wireless communication terminal belonging to a specific BSS may receive a WUR beacon frame or a wake-up frame from the base wireless communication terminal of the OBSS using the same identifier as the corresponding BSS. In this case, the wireless communication terminal can determine that the wireless communication terminal is not the intended recipient only after confirming the embedded BSSID through the FCS calculation for the received WUR beacon frame or the wake-up frame. As a result, unnecessary power consumption may increase. The operation of detecting the WUR frame by the wireless communication terminal and performing the FCS calculation is because a larger amount of power may be consumed than maintaining the power of the PCR transceiver for a predetermined time. In addition, the probability that an unintended wake-up for a wireless communication terminal is induced can be increased. Accordingly, the base wireless communication terminal needs to determine the WUR identifiers in an efficient manner. For example, a WUR identifier allocation method may be used that reduces the situation in which the same WUR identifier is used on a single WUR identifier space. Hereinafter, a method of determining the TXID, the NTXID, the WUR STA ID, and the WUR group ID will be described in detail.

According to an embodiment, a WUR STA ID and a WUR group ID for identifying a group of wireless communication terminals or a wireless communication terminal combined with a base wireless communication terminal may be determined based on the TXID of the corresponding base wireless communication terminal. Accordingly, it may be advantageous for TXIDs identifying each of the different base wireless communication terminals to be distributed as possible over the WUR identifier space. This is because the smaller the difference between the values of TXIDs identifying different base wireless communication terminals on the WUR identifier space, the greater the probability that the overlapped WUR STA ID or WUR group ID is used.

15 is a diagram illustrating a method of obtaining a TXID based on a BSSID of a base wireless communication terminal according to an embodiment of the present invention. According to an embodiment of the present invention, the TXID may be a value determined based on the BSSID of the base wireless communication terminal. For example, the wireless communication terminal and the base wireless communication terminal may determine a TXID identifying the base wireless communication terminal based on the BSSID of the base wireless communication terminal.

In addition, when the base wireless communication terminal operates a multiple basic service set identifier (BSSID) set, the TXID may be a value obtained based on a transmitted BSSID (BSSID) transmitted from among the plurality of BSSIDs. Here, the transmitted BSSID may be a MAC address unique to the base wireless communication terminal. The transmitted BSSID may be a representative BSSID representing a multiple BSSID set operated by the base wireless communication terminal. Specifically, the transmitted BSSID may be a representative BSSID used for transmission of a management frame for all of the plurality of BSSs operated by the base wireless communication terminal. At this time, the transmission of the management frame may be performed through PCR. The multiple BSSID set may consist of one transmitted BSSID and at least one untransmitted BSSID. In this case, the transmitted BSSID may be a BSSID used regardless of whether the base wireless communication terminal operates a multi-BSSID set. That is, when the base wireless communication terminal operates multiple BSSID sets, the transmitted BSSID of the base wireless communication terminal may indicate a BSSID when the base wireless communication terminal does not operate the multiple BSSID sets. The BSSID of the base wireless communication terminal may be a transport address signaled in the MAC layer. In this case, the BSSID (or transmitted BSSID) may be transmitted from the base wireless communication terminal to the wireless communication terminal through a beacon frame. Here, the beacon frame may be a PCR beacon frame transmitted through the PCR. In the embodiment of FIG. 15, the BSSID may be used to mean a transmitted BSSID.

According to an embodiment, the TXID may be a value obtained based on a part of the transmitted BSSID. For example, the TXID may be obtained from a bit of a predetermined position among bits constituting the BSSID. The preset position may be a position set based on at least one of a most significant bit (MSB) or a least significant bit (LSB). For example, the TXID may be a predetermined number of MSBs among the bits of the BSSID. Alternatively, the TXID may be a predetermined number of LSBs among the bits of the BSSID. In this case, the preset number may be 12.

According to another embodiment, the TXID may be a value obtained based on the compressed BSSID of the base wireless communication terminal. Here, the compressed BSSID may be a value obtained by performing a 32-bit CRC operation on the original BSSID. For example, the TXID may be obtained from a bit of a predetermined position among bits constituting the compressed BSSID. The preset position may be a position set based on at least one of MSB and LSB. For example, the TXID may be a predetermined number of MSBs among bits constituting the compressed BSSID. Alternatively, the TXID may be a predetermined number of LSBs among bits constituting the compressed BSSID. In this case, the preset number may be 12.

According to another embodiment, the TXID may be a value obtained by hashing a BSSID. For example, the base wireless communication terminal may generate a plurality of sequence sets by dividing the bits representing the BSSID into predetermined units. In addition, the base wireless communication terminal may hash the plurality of sequence sets to obtain a TXID. In detail, the preset unit may be 12-bit. In this case, four sequence sets can be generated. The TXID may be a value obtained by performing an XOR operation on at least two or more of the four sequence sets generated.

16 is a diagram illustrating a method of obtaining a TXID according to another embodiment of the present invention. According to one embodiment of the invention, a separate set of TXIDs, including a plurality of preset values, for the TXID may be managed. In this case, the preset value may be a value set such that it cannot be used as a WUR identifier other than TXID among values in the WUR identifier space. The preset value may be a value of 12-bit. The TXID set may be some of the values representable using 12-bit. The TXID of the specific base wireless communication terminal may be any one of a plurality of preset values. For example, the base wireless communication terminal may select any one of a plurality of preset values to obtain a TXID. Through this, the TXID of the specific base wireless communication terminal may not be used as at least the WUR STA ID or the WUR group ID of the specific group belonging to the OBSS. The TXID may be a WUR identifier transmitted most frequently through the WUR.

According to an embodiment, the plurality of preset values included in the TXID set may include a common part. The common part may indicate a preset position where the plurality of preset values have the same bit value. For example, when a plurality of preset values are represented by N bits, the bits of at least M preset positions among the N bits may be the same value. In this case, N may be an integer, and M may be an integer smaller than N. Referring to FIG. 16A, the common part may be a specific number of consecutive zero or one MSBs. In this case, the TXID may include a certain number of consecutive zero or one MSBs. Referring to FIG. 16B, the common part may be a specific number of consecutive zero or one LSBs. In this case, the TXID may include a certain number of consecutive zero or one LSBs. Referring again to FIG. 16A, when the common part is an MSB, a plurality of preset values may be located in a specific part of the WUR identifier space. On the other hand, when the common part is the LSB, the wireless communication terminal can identify the TXID using the MSB of the TXID. Accordingly, the wireless communication terminal can more efficiently determine whether the TXID of the received WUR frame is the TXID of the OBSS, compared to the case where the common part is the MSB. For example, if the wireless communication terminal determines that the TXID of the WUR frame received through the MSB of the TXID is the TXID of the OBSS, the wireless communication terminal may further reduce power consumption by stopping reception of the WUR frame.

According to a further embodiment, when the base radio communication terminal of the BSS conforms to the standard after the IEEE 802.11ax, except for the common part in the TXID of the base radio communication terminal based on the BSS color of the base radio communication terminal (Color) Can be determined. For example, when the BSS color of the base wireless communication terminal is '101010' and the common part is a 6-bit consecutive 0 or 1 LSB, the TXID of the base wireless communication terminal may be '101010000000' or '101010111111'. have.

17 is a diagram illustrating a method of obtaining a TXID according to another embodiment of the present invention. According to an embodiment of the present invention, the TXID of a specific base wireless communication terminal may be determined based on the aforementioned common part and the BSSID of the base wireless communication terminal. In the embodiment of FIG. 17, the BSSID may be used to mean a transmitted BSSID. For example, the common part of the TXID may be determined in the same or corresponding method as the method described with reference to FIG. 16. The remaining part constituting the TXID other than the common part of the TXID may be determined based on the BSSID. Specifically, if the common part of the 12-bit constituting the TXID is an 8-bit LSB or MSB, 4-bit, the remaining part constituting the TXID using the BSSID of the base wireless communication terminal may be generated.

According to an embodiment, the remaining part of the TXID may be obtained from the bit of the preset position among the bits of the BSSID. The preset position may be a position set based on at least one of MSB and LSB. For example, the TXID may be consecutive bits of the BSSID from the MSB of the BSSID to a preset number. Alternatively, the TXID may be consecutive bits of the BSSID from the LSB of the BSSID to a preset number. The preset number may be a number N-M obtained by subtracting the number M of bits corresponding to the common part from the total number N of bits constituting the TXID.

According to another embodiment, the remaining part of the TXID may be a value obtained by hashing the BSSID. For example, the base wireless communication terminal may generate a plurality of sequence sets by dividing the bits representing the BSSID into predetermined units. In addition, the base wireless communication terminal may hash the plurality of sequence sets to obtain the remaining portion of the TXID. The preset unit may be a number N-M obtained by subtracting the number M of bits corresponding to the common part from the total number N of bits constituting the TXID. In detail, when the preset unit is 4-bit, twelve sequence sets may be generated. The remaining part of the TXID may be a value obtained by performing an XOR operation on at least two or more of the 12 sequence sets generated.

In this way, the base wireless communication terminal can estimate a region in which the WUR identifiers of the OBSS are distributed in the WUR identifier space based on the BSSID of another base wireless communication terminal belonging to the OBSS. In this case, the base wireless communication terminal may receive a BSSID of the base wireless communication terminal belonging to the OBSS from the wireless communication terminal connected to the base wireless communication terminal. For example, the wireless communication terminal may receive a PCR beacon frame transmitted from the OBSS through the PCR transceiver. In this case, the wireless communication terminal may transmit the BSSID of the base wireless communication terminal belonging to the OBSS to the base wireless communication terminal of the BSS to which the wireless communication terminal belongs, through a report procedure such as an event report.

According to an embodiment of the present invention, the TXID may be used for transmission of at least one of a broadcast wake-up frame or a WUR beacon frame of a BSS operated by the corresponding base wireless communication terminal. For example, the base wireless communication terminal may insert a TXID in at least one ID field of a broadcast wake-up frame or a WUR beacon frame. In addition, the wireless communication terminal may obtain the TXID from the BSSID of the base wireless communication terminal associated with the wireless communication terminal in a predetermined method between the base wireless communication terminal and the wireless communication terminal. In this case, the predetermined method may be any one of the above-described methods. The wireless communication terminal may determine whether the wireless communication terminal is an intended recipient of the corresponding WUR frame based on the obtained TXID. In addition, the wireless communication terminal may perform an operation indicated by the WUR frame based on the determination result.

Meanwhile, when the base wireless communication terminal operates multiple BSSIDs, the base wireless communication terminal may communicate with the plurality of wireless communication terminals based on the plurality of BSSIDs included in the multiple BSSID set. In this case, the multi-BSSID set may consist of one transmitted BSSID and at least one untransmitted BSSID. The BSS corresponding to each of the at least one unsent BSSID may be referred to as an unsent BSS. As described above, the plurality of BSSs operated by one base wireless communication terminal may be identified through different WUR identifiers, respectively. In addition, the plurality of BSSs may be identified using one TXID and a specific number of NTXIDs, respectively. At this time, the number of NTXID may be the number of untransmitted BSS.

Each NTXID is a WUR identifier that identifies a specific BSS operated by the base wireless communication terminal, similar to the TXID. In addition, the NTXID may be used for transmission of a broadcast wake-up frame that induces wake-up for all wireless communication terminals belonging to the BSS indicated by the NTXID. In this case, the broadcast wake-up frame may not include a frame body field. For example, the base wireless communication terminal may insert the NTXID in the ID field of the broadcast wake-up frame that addresses all wireless communication terminals associated with the BSS indicated by the NTXID. In addition, the base wireless communication terminal and the wireless communication terminal can obtain the NTXID of the BSS associated with the wireless communication terminal in a predetermined method between the base wireless communication terminal and the wireless communication terminal. Hereinafter, a method of obtaining an NTXID will be described in detail.

According to an embodiment of the present invention, the NTXID may be obtained based on the TXID of the base wireless communication terminal. For example, the base wireless communication terminal may determine NTXIDs corresponding to each of the at least one BSS based on the TXID. The wireless communication terminal may obtain a TXID from the base wireless communication terminal. For example, the NTXID of the untransmitted BSS corresponding to the base wireless communication terminal may be a value around the TXID of the base wireless communication terminal on the WUR identifier space. According to an embodiment, the NTXID of the untransmitted BSS corresponding to the base wireless communication terminal may be allocated in descending order from a value smaller than the TXID of the base wireless communication terminal and closest to the TXID. For example, the NTXID of a particular untransmitted BSS may be any one of k adjacent values smaller than the TXID. In this case, k may be the number of untransmitted BSSs (or untransmitted BSSIDs) operated by the base wireless communication terminal.

According to another embodiment, the NTXID of the untransmitted BSS corresponding to the base wireless communication terminal may be allocated in ascending order from a value larger than the TXID of the base wireless communication terminal and closest to the TXID. The NTXID of a particular untransmitted BSS may be any one of k adjacent values greater than the TXID. In this case, k may be the number of untransmitted BSSs (or untransmitted BSSIDs) operated by the base wireless communication terminal. The values from TXID to TXID + k on the WUR identifier space may be used as a value for identifying each of the plurality of BSSs operated by the base wireless communication terminal. Each of the values from TXID to TXID + k may be used as a WUR identifier for inducing wake-up of all wireless communication terminals associated with each of the plurality of BSSIDs operated by the base wireless communication terminal. The base wireless communication terminal may induce wake-up of wireless communication terminals associated with each of a plurality of BSSs operated by the base wireless communication terminal. In this case, the base wireless communication terminal may use values from TXID to TXID + k as a WUR identifier for identifying each of the plurality of BSSs operated by the base wireless communication terminal.

Specifically, the NTXID of the unsent BSS may be obtained based on the TXID and the BSSID index. Here, the BSSID index is an integer from 1 to k allocated to each of the untransmitted BSSs included in the multiple BSSID set operated by the base wireless communication terminal. The BSSID index may be a value assigned to each of the untransmitted BSSs included in the multiple BSSID set by the base wireless communication terminal. In addition, the base wireless communication terminal may transmit BSSID index information allocated to the BSS to wireless communication terminals belonging to a specific BSS. The base wireless communication terminal may determine the NTXID of each of the untransmitted BSSs operated by the base wireless communication terminal based on the TXID and the BSSID index of the base wireless communication terminal. For example, NTXID (n) of the nth untransmitted BSS may be TXID + n.

The wireless communication terminal can obtain BSSID index information of the untransmitted BSS to which the wireless communication terminal belongs from the base wireless communication terminal. For example, the wireless communication terminal may receive an element including a BSSID index of an untransmitted BSS to which the wireless communication terminal belongs from the base wireless communication terminal. In this case, an element including a BSSID index may be referred to as a multiple BSSID index element. The wireless communication terminal can obtain the NTXID of the untransmitted BSS to which the wireless communication terminal belongs based on the TXID and the BSSID index information of the untransmitted BSS to which the wireless communication terminal belongs. For example, the wireless communication terminal can calculate the NTXID of the untransmitted BSS to which the wireless communication terminal belongs by adding the BSSID index to the TXID. In addition, the wireless communication terminal can determine whether the wireless communication terminal is the intended recipient of the received WUR frame by using the NTXID of the untransmitted BSS to which the wireless communication terminal belongs. A method of determining whether the wireless communication terminal is the intended recipient of the received WUR frame will be described later.

The NTXID of the untransmitted BSS obtained by the above method may be used as a WUR identifier for inducing wake-up of all wireless communication terminals belonging to the untransmitted BSS. For example, the base wireless communication terminal may insert the first NTXID of the first untransmitted BSS into the ID field of the WUR frame. In this case, the WUR frame may not include the frame body field. The WUR frame may be a frame of fixed length to a preset value. That is, the Length Present field of the WUR frame may represent that the WUR frame does not include the frame body. In addition, the frame type of the WUR frame may be a wake-up frame. The base wireless communication terminal may transmit a WUR frame including the first NTXID to trigger wake-up of wireless communication terminals belonging to the first untransmitted BSS. The base wireless communication terminal may broadcast a WUR frame including the first NTXID to all wireless communication terminals belonging to the first untransmitted BSS. When the wireless communication terminal belonging to the first non-transmitted BSS receives the WUR frame including the first NTXID, the wireless communication terminal may wake up based on the corresponding WUR frame.

According to a further embodiment, when the base wireless communication terminal uses multiple BSSID sets, all BSS transmitter IDs (ATXIDs) for identifying all the wireless communication terminals associated with the base wireless communication terminal may be defined separately. have. According to an embodiment, the ATXID may be a value determined based on the TXID of the base wireless communication terminal corresponding to the ATXID. The ATXID may be a 12-bit value. For example, the ATXID may be a value adjacent to the TXID and / or NTXID of the base wireless communication terminal corresponding to the ATXID in the WUR identifier space. For example, when the NTXID is determined to be larger than the TXID, the ATXID may be (TXID-1). If the NTXID is determined to be smaller than the TXID, the ATXID may be (TXID + 1). TXID, NTXID and ATXID may be set to values adjacent to each other, and the order on the WUR identifier space may vary depending on the implementation.

According to an embodiment of the present invention, values other than TXID to (TXID + k) (including ATXID when including ATXID) on the WUR identifier space may be used as a WUR identifier for identifying an individual wireless communication terminal or group. have. According to a specific embodiment, when the common part of the TXID is LSB as shown in FIGS. 16B and 17, values other than TXID to TXID + k on the WUR identifier space may be used as the WUR STA ID or the WUR group ID. . In this case, the WUR STA ID or the WUR group ID may be any one of values other than TXID to (TXID + k).

According to an embodiment, the WUR STA ID and the WUR group ID may be determined based on the TXID of the base wireless communication terminal. The first WUR STA ID of the first wireless communication terminal may be a value close to the TXID of the base wireless communication terminal to which the first wireless communication terminal belongs in the WUR identifier space. Specifically, the first WUR STA ID may be determined based on the first TXID of the first base wireless communication terminal associated with the first wireless communication terminal. For example, the first WUR STA ID may be a value obtained by adding a preset offset to the first TXID. In this case, when the first base wireless communication terminal uses a multiple BSSID set, the preset offset may be greater than the number k of untransmitted BSSs operated by the first base wireless communication terminal.

For example, when the common part of the first TXID is an 8-bit consecutive zero LSB and the remaining part is 0xA00, the WUR STA ID and / or the WUR group ID of the wireless communication terminals associated with the first base wireless communication terminal are It may be determined as a value between 0xA01-0xAFF. Through this, it is possible to reduce the situation in which the WUR identifiers overlap between BSSs having different transmitted BSSIDs by using the WUR identifiers in a concentrated range for each transmitted BSSID. This may be more effective in a dense environment of BSS. In addition, the wireless communication terminal can estimate which WUR identifiers are used in the external BSS through the WUR beacon frame transmitted by the external BSS.

In addition, when the WUR STA ID and / or the WUR group ID are allocated to the wireless communication terminals based on the TXID, the base wireless communication terminal transmits the changed TXID to change the WUR STA IDs of all terminals associated with the base wireless communication terminal. Can be. The base wireless communication terminal may transmit the changed TXID through the PCR broadcast WUR action frame. In this case, the base wireless communication terminal may not transmit the change of the WUR STA ID assigned to each of the wireless communication terminals. The wireless communication terminals may obtain the changed WUR STA ID and / or the WUR group ID based on the changed TXID.

For example, the first terminal may calculate the changed WUR STA ID and / or the WUR group ID of the first terminal based on the positional relationship between the before-change WUR STA ID and the before-change TXID on the WUR identifier space. Can be. Specifically, when the WUR STA ID before the change of the first terminal is 0xB03 and the TXID of the base wireless communication terminal is changed from 0xB00 to 0x700, the changed WUR STA ID of the first terminal may be determined as 0x703.

Also, the preset offset may be a value within a preset range. All values of a preset range from the TXID of the base wireless communication terminal may be exhausted in the assignment of the WUR identifier associated with the base wireless communication terminal. In this case, the base wireless communication terminal may preferentially use adjacent values outside the preset range from the TXID of the base wireless communication terminal on the WUR identifier space. Specifically, the base wireless communication terminal may assign a value of a range set based on a TXID other than the TXID of the base wireless communication terminal as a value for identifying each wireless communication terminal to wireless communication terminals associated with the base wireless communication terminal. . For example, the base wireless communication terminal may use an additional second TXID other than the first TXID.

When the base wireless communication terminal uses the first TXID and the second TXID, the base wireless communication terminal may transmit the first TXID and the second TXID to all wireless communication terminals associated with the base wireless communication terminal. Alternatively, the base wireless communication terminal may transmit the first TXID to the wireless communication terminals identified through the WUR identifier of the range set based on the first TXID. In addition, the base wireless communication terminal may transmit the second TXID to the wireless communication terminals identified through the WUR identifier of the range set based on the second TXID. In addition, the base wireless communication terminal may transmit a separate beacon frame based on each of the first TXID and the second TXID.

According to an embodiment, the first base wireless communication terminal may allocate a WUR STA ID to a plurality of wireless communication terminals associated with the first base wireless communication terminal based on the AID. For example, the preset offset added to the first TXID may be sequentially increased. The first base wireless communication terminal may allocate WUR STA IDs sequentially increasing from the next value of (first TXID + k) to each of the plurality of wireless communication terminals associated with the first base wireless communication terminal. In this way, WUR STA IDs not overlapping each other may be allocated to each of the plurality of wireless communication terminals associated with the first base wireless communication terminal.

According to an embodiment, a value obtained by adding a preset offset to a TXID may be a value used as a TXID of a second base wireless communication terminal different from the first base wireless communication terminal or an NTXID of the second base wireless communication terminal. In this case, the first base wireless communication terminal may exclude the corresponding value on the WUR identifier space. For example, the first base wireless communication terminal may allocate the next value of the corresponding value to the specific wireless communication terminal on the WUR identifier space. In addition, an S-bit modulo operation may be used in the process of assigning a WUR STA ID or a WUR group ID. This is because the WUR identifier space is limited to a range that can be expressed using a predetermined number of bits. Accordingly, S may be a preset number defining the WUR identifier space. According to one embodiment, S may be '12'.

According to another embodiment, the WUR STA ID may be assigned to each wireless communication terminal in a random manner. Even in this case, the plurality of wireless communication terminals associated with the first base wireless communication terminal may be configured to allocate WUR STA IDs that are not duplicated with each other. The WUR group ID for identifying a group of wireless communication terminals combined with a specific base wireless communication terminal may be determined in the same or corresponding manner to the manner in which the above-described WUR STA ID is determined.

Hereinafter, a method of determining a WUR group ID in a WUR identifier space according to another embodiment of the present invention will be described in detail with reference to FIG. 18. 18 illustrates a WUR group ID space (hereinafter, 'GID space') according to an embodiment of the present invention. According to an embodiment of the present invention, the WUR group ID may be a value in a GID space. In this case, the GID space may be an area within the WUR identifier space set based on the TXID of the base wireless communication terminal associated with the GID space. In this case, the size of the GID space may be set to a different value according to the base wireless communication terminal associated with the GID space. In addition, the size of the GID space may not be explicitly transmitted to the wireless communication terminal. According to an embodiment, when the ID field of the fixed-length wake-up frame includes the first WUR group ID, wake-up of all the wireless communication terminals included in the first group identified by the first WUR group ID Can be derived.

 According to another embodiment, when the ID field of the wake-up frame of the variable length includes a second WUR group ID, at least one of at least one wireless communication terminal included in the second group identified by the second WUR group ID It can induce wake-up of some terminals. In this case, the wireless communication terminal from which the wake-up is induced among the at least one wireless communication terminal included in the second group may be determined based on the frame body field of the wake-up frame. In this case, wireless communication terminals not included in the second group among the wireless communication terminals receiving the wake-up frame may stop receiving the wake-up frame based on the ID field of the wake-up frame. Through this, the wireless communication terminal can obtain an additional power save effect.

According to an embodiment of the present invention, the base wireless communication terminal may induce wake-up of a plurality of terminals not included in a specific group. In this case, the base wireless communication terminal may transmit a separate wake-up frame to each of the wireless communication terminals. Alternatively, the base wireless communication terminal may transmit a VL wake-up frame having a variable length to induce wake-up of a plurality of terminals. In this case, the identifier field of the VL wake-up frame may include an identifier for identifying all terminals associated with the base wireless communication terminal. For example, an identifier identifying all terminals associated with the base wireless communication terminal may be inserted into the ID field. For example, the base radio communication terminal may insert one of the TXID, the ATXID of the base radio communication terminal, and the NTXID identifying each of the plurality of untransmitted BSSs operated by the base radio communication terminal into the ID field of the VL wake-up frame. Can be. In addition, the Frame Body field of the VL wake-up frame may include a plurality of WUR STA IDs that identify each of the plurality of wireless communication terminals from which the wake-up is induced.

According to a further embodiment, the base wireless communication terminal may manage a separate WUR group ID for the above-described situation. This is because TXID, ATXID, and NTXID may be difficult to use in the ID field of the wake-up frame because they are WUR identifiers used for WUR beacon frames or broadcast frames. In this case, the GID space may be utilized in the same or corresponding method as the method of determining the TXID and the NTXID described above with reference to FIGS. 15 to 17. For example, a TX Group ID (TGID) identifying a group consisting of all wireless communication terminals associated with a base wireless communication terminal corresponding to a TXID, NTX identifying a group consisting of all wireless communication terminals in the BSS identified by the NTXID. A WUR Group ID (NTGID) and an ATX Group ID (ATGID) identifying a group consisting of all wireless communication terminals in all BSSs identified by the ATXID may be managed. The TGID, NTGID, and ATGID may be allocated in the same or corresponding manner as the above-described TXID allocation method. In addition, TGID, NTGID, and ATGID associated with one base wireless communication terminal may be values adjacent to each other on a WUR identifier space.

As described above with reference to FIG. 8, the wireless communication terminal may receive a WUR frame through the WURx from the base wireless communication terminal. At this time, the wireless communication terminal can determine whether the wireless communication terminal is the intended recipient of the received WUR frame. The wireless communication terminal can determine whether the wireless communication terminal is the intended recipient of the received WUR frame based on the identifier included in the received WUR frame. Specifically, the wireless communication terminal may determine whether the wireless communication terminal is the intended recipient of the received WUR frame based on at least one of the Type field, the ID field, or the Frame Body field of the received WUR frame. Hereinafter, a method of determining by the wireless communication terminal whether the wireless communication terminal is the intended recipient of the received WUR frame will be described in detail.

According to an embodiment, the wireless communication terminal may determine whether the wireless communication terminal is an intended recipient of the received WUR frame based on the identifier of the WUR frame. For example, the wireless communication terminal can compare the ID field of the received WUR frame with the WUR identifier corresponding to the wireless communication terminal to determine whether the wireless communication terminal is the intended recipient of the received WUR frame. In detail, the WUR identifier corresponding to the wireless communication terminal may include at least one of a WUR STA ID of the wireless communication terminal and a WUR group ID of a group to which the wireless communication terminal belongs. In addition, the WUR identifier corresponding to the wireless communication terminal may include the TXID of the base wireless communication terminal combined with the wireless communication terminal.

On the other hand, when the base wireless communication terminal combined with the wireless communication terminal uses a multi-BSSID set, the WUR identifier corresponding to the wireless communication terminal may include an identifier for identifying the BSS to which the wireless communication terminal belongs. According to an embodiment of the present invention, when a wireless communication terminal receives a wake-up frame, the wireless communication terminal receives the wireless communication terminal according to whether the base wireless communication terminal combined with the wireless communication terminal uses multiple BSSID sets. It can be determined whether it is the intended recipient of the wake-up frame.

For example, if the ID field of the received wake-up frame indicates the TXID of the base wireless communication terminal combined with the wireless communication terminal, the wireless communication terminal is received according to whether the base wireless communication terminal operates multiple BSSID sets. It can be determined whether it is the intended recipient of the WUR frame. According to an embodiment, when the BSS to which the wireless communication terminal belongs does not correspond to the multiple BSSID set, the wireless communication terminal may determine that the wireless communication terminal is an intended recipient of a wake-up frame in which the ID field indicates the TXID. . In this case, the wireless communication terminal can determine whether the WUR frame is valid using the FCS field.

According to another embodiment, when the base wireless communication terminal operates a multi-BSSID set, the plurality of wireless communication terminals combined with the base wireless communication terminal may be a terminal belonging to any one of the transmitted BSS or the untransmitted BSS, respectively. have. In this case, when the BSS to which the wireless communication terminal belongs is any one of the untransmitted BSSs, the wireless communication terminal may determine that the wireless communication terminal is not the intended receiver of the wake-up frame in which the ID field indicates the TXID. Conversely, if the BSS to which the wireless communication terminal belongs is a transmitted BSS, the wireless communication terminal may determine that the wireless communication terminal is not the intended recipient of the wake-up frame in which the ID field indicates the TXID. In this case, the wireless communication terminal may stop receiving the WUR frame without determining whether the WUR frame is valid using the FCS field.

In detail, the base wireless communication terminal uses multiple BSSID sets, and the first wireless communication terminal combined with the corresponding base wireless communication terminal may be a terminal belonging to an untransmitted BSS. In this case, the wireless communication terminal may receive a WUR frame in which the ID field indicates the TXID of the base wireless communication terminal. If the frame type of the WUR frame is a wake-up frame and the ID field of the WUR frame indicates the TXID of the base wireless communication terminal, the first wireless communication terminal determines that the first wireless communication terminal is not the intended recipient of the WUR frame. can do. In this case, the wireless communication terminal may stop receiving the WUR frame without determining whether the WUR frame is valid using the FCS field. On the other hand, if the frame type of the received WUR frame is a WUR beacon frame, the first wireless communication terminal can determine that the first wireless communication terminal is the intended recipient of the WUR beacon frame. The ID field of the WUR beacon frame will be described later in other parts of the present disclosure.

According to an embodiment, when the base wireless communication terminal uses a multiple BSSID set, each of the plurality of wireless communication terminals combined with the base wireless communication terminal has a WUR identifier for identifying a BSS to which each of the plurality of wireless communication terminals belongs. Can be used to determine if it is included in the intended recipient of the wake-up frame. In this case, the wake-up frame may be a frame broadcast to all wireless communication terminals belonging to the corresponding BSS through the WUR. For example, the first wireless communication terminal determines whether the first wireless communication terminal is the intended recipient of the wake-up frame by using the first NTXID, which is a WUR identifier that identifies the first untransmitted BSS to which the first wireless communication terminal belongs. can do. That is, when the BSS to which the wireless communication terminal belongs is an untransmitted BSS, the WUR identifier corresponding to the wireless communication terminal may include an NTXID identifying the BSS to which the wireless communication terminal belongs. In this case, the first wireless communication terminal may obtain the first NTXID based on the TXID as described above. The first wireless communication terminal may determine whether the ID field of the received wake-up frame includes the first NTXID. In addition, when the ID field includes the first NTXID, the first wireless communication terminal may wake up the PCR transceiver of the first wireless communication terminal based on the wake-up frame.

Conversely, if the base wireless communication terminal does not use multiple BSSID sets and the ID field of the WUR frame indicates the TXID, the second wireless communication terminal may determine that the second wireless communication terminal is the intended recipient of the WUR frame. . In this case, the wireless communication terminal can determine whether the WUR frame is valid using the FCS field. Also, if the WUR frame is valid, the second wireless communication terminal can wake up based on the wake-up frame that includes the TXID identifying the base wireless communication terminal associated with the second wireless communication terminal.

Meanwhile, when the base wireless communication terminal uses multiple BSSID sets, the base wireless communication terminal may transmit a WUR beacon frame using a WUR identifier common to all BSSs corresponding to the multiple BSSID sets. The WUR Beacon frame does not contain individual information about the WUR service, but may include TSF information. Accordingly, it may be inefficient to generate and transmit a WUR beacon frame in which different identifiers are inserted for each BSS.

According to one embodiment, the common WUR identifier may be a WUR identifier corresponding to a representative BSSID (or representative BSS) representing a multiple BSSID set. For example, the common WUR identifier may be the TXID of the base wireless communication terminal. The base radio communication terminal may insert the TXID into the ID field of the WUR beacon frame of all BSSs operated by the base radio communication terminal. The WUR beacon frame will be described in detail with reference to FIG. 19. In this case, the wireless communication terminal can determine whether the wireless communication terminal is the intended recipient of the received WUR frame based on the frame type of the WUR frame. Specifically, the wireless communication terminal may determine, according to the frame type of the WUR frame, whether the wireless communication terminal is the intended recipient of the WUR frame including the TXID as an identifier.

According to an embodiment of the present invention, the base wireless communication terminal and the wireless communication terminal uses a multi-BSSID set, the wireless communication terminal may be a terminal belonging to an untransmitted BSS. In this case, the wireless communication terminal can determine whether the wireless communication terminal is the intended recipient of the WUR frame based on whether the WUR frame type is a WUR beacon frame transmitted periodically.

For example, if the frame type of the WUR frame is a WUR beacon frame, the wireless communication terminal may be the intended recipient of the WUR frame that includes the TXID as an identifier. When the wireless communication terminal receives a WUR beacon frame including the TXID as an identifier, the wireless communication terminal may determine that the wireless communication terminal is an intended recipient of the received WUR frame. If the frame type of the received WUR frame is a beacon frame and the ID field includes TXID, the wireless communication terminal is an intended receiver of the WUR frame received by the wireless communication terminal regardless of whether the BSS is a BSS corresponding to a multiple BSSID set. It can be judged that In this case, the wireless communication terminal can determine whether the WUR frame is valid using the FCS field. In addition, if the WUR frame is valid, subsequent operations indicated by the WUR beacon frame may be performed. For example, the wireless communication terminal may update time information of the wireless communication terminal based on the WUR beacon frame. If the WUR frame type is not a WUR beacon frame, the wireless communication terminal may not be the intended recipient of the WUR frame that includes the TXID as an identifier. In this case, the wireless communication terminal may stop receiving the WUR frame without determining whether the WUR frame is valid using the FCS field.

Alternatively, the wireless communication terminal may determine whether the wireless communication terminal is the intended recipient of the WUR frame based on whether the WUR frame type is a wake-up frame indicating the wake-up of the wireless communication terminal. For example, if the WUR frame type is a wake-up frame, the wireless communication terminal may not be the intended recipient of the WUR frame that includes the TXID as an identifier.

 According to an embodiment of the present invention, when the received WUR frame is a variable length frame, the wireless communication terminal may determine whether the wireless communication terminal is an intended recipient of the received WUR frame based on the ID field and the frame body of the WUR frame. Can be. In this case, the frame type of the WUR frame may be a wake-up frame. In addition, the transmission scheme of the WUR frame may be a broadcast or group cast scheme. For example, the wireless communication terminal may determine whether the received WUR frame is a variable length frame based on the Length Present field of the received WUR frame. The Frame body field of the WUR frame may include a WUR STA ID corresponding to at least one wireless communication terminal.

In detail, when the ID field includes the TXID, the frame body field may include a WUR identifier for identifying at least some of the plurality of wireless communication terminals combined with the base wireless communication terminal indicated by the TXID. When the ID field includes an NTXID, the frame body field may include a WUR identifier for identifying at least some of a plurality of wireless communication terminals belonging to a BSS indicated by the NTXID. When the ID field includes a WUR group ID, the frame body field may include a WUR identifier for identifying at least some of the plurality of wireless communication terminals of the group indicated by the WUR group ID.

The wireless communication terminal may determine whether to receive the Frame Body field based on the ID field. For example, if the received WUR frame is a variable length frame and the ID field of the WUR frame includes any one of TXID, NTXID, or WUR group ID associated with the wireless communication terminal, the wireless communication terminal includes the Frame body field. Based on the WUR identifier, it may be determined whether the wireless communication terminal is the intended recipient of the received WUR frame. On the other hand, if the ID field of the WUR frame is not any one of the TXID, NTXID, or WUR group ID associated with the wireless communication terminal, the wireless communication terminal may stop receiving the WUR frame.

As described above, the wireless communication terminal can determine whether the wireless communication terminal is the intended recipient of the received WUR frame. Next, the wireless communication terminal may perform a preset subsequent operation based on the determination result. The wireless communication terminal may determine whether to perform an operation of determining whether the WUR frame is valid through the FCS field based on the determination result. According to an embodiment, when the wireless communication terminal is an intended recipient of the WUR frame, the wireless communication terminal may determine whether the WUR frame is valid using the FCS field.

Specifically, the wireless communication terminal may generate the FCS value based on the plurality of field values included in the WUR frame. In addition, the wireless communication terminal may determine whether the WUR frame is successfully received by comparing the generated FCS value and the value of the received FCS field. Additionally, the wireless communication terminal may compare the generated FCS value with the value of the received FCS field to determine whether the embedded BSSID identifies the base wireless communication terminal combined with the wireless communication terminal. In this case, the wireless communication terminal may generate an FCS value based on the BSSID of the base wireless communication terminal combined with the wireless communication terminal. On the other hand, if the wireless communication terminal is not the intended recipient of the WUR frame, the wireless communication terminal may not determine the validity of the WUR frame using the FCS field. That is, the wireless communication terminal may not generate the FCS value based on the plurality of field values included in the WUR frame.

As described above, when the wireless communication terminal determines that there is no error in the WUR frame using the FCS field, the wireless communication terminal may perform a subsequent operation according to the WUR frame. For example, if the wireless communication terminal is the intended recipient of a WUR frame, the wireless communication terminal may perform subsequent operations determined based on the WUR frame. Here, the subsequent operation determined based on the WUR frame may include an operation performed through the PCR transceiver of the wireless communication terminal or an operation performed through the WURx.

According to an embodiment, when the WUR frame is a WUR beacon frame, the wireless communication terminal may perform a subsequent operation indicated by the WUR beacon frame. For example, the wireless communication terminal may perform time synchronization based on time synchronization function (TSF) information included in the WUR beacon frame. In addition, when the WUR beacon frame includes an indicator indicating the reception of the PCR beacon frame, the wireless communication terminal may wake up the PCR transceiver for receiving the PCR beacon frame. According to another embodiment, when the WUR frame is a wake-up frame, the wireless communication terminal may wake up the PCR transceiver of the wireless communication terminal based on the WUR frame.

On the other hand, when the wireless communication terminal communicating with the base wireless communication terminal via PCR is out of the transmission coverage of the base wireless communication terminal, the wireless communication terminal may determine that the connection with the base wireless communication terminal (connection lost). In this case, the wireless communication terminal may perform a scan procedure for association with a new BSS. In more detail, the wireless communication terminal may attempt to connect with a corresponding base wireless communication terminal based on a beacon frame transmitted by the new base wireless communication terminal.

In the PCR dose state, the wireless communication terminal cannot receive the beacon frame transmitted by the PCR. Also, the wireless communication terminal cannot transmit any MAC frame through PCR unless the wireless communication terminal receives the wake-up frame to turn on the PCR transceiver and turn on the PCR transceiver for PCR transmission. Therefore, it may be difficult for the wireless communication terminal in the PCR dose state to determine whether the wireless communication terminal is out of the transmission coverage of the base wireless communication terminal. In addition, the wireless communication terminal may continue to maintain the PCR dose state even if it is out of the transmission coverage of the base wireless communication terminal. For efficient operation of the wireless communication terminal, the base wireless communication terminal may transmit the WUR beacon frame periodically through the WUR. Hereinafter, a method of transmitting a WUR beacon frame will be described in detail with reference to FIG. 19, and in particular, an operation of a wireless communication terminal associated with a WUR identifier that can be included in an ID field of a WUR beacon frame will be described.

19 is a diagram illustrating a method for receiving a WUR beacon frame by a wireless communication terminal according to an embodiment of the present invention. As described above, the WUR beacon frame is a type of WUR frame and may be transmitted through a WUR PPDU. The WUR beacon frame may include time synchronization function (TSF) information so that the wireless communication terminal in the PCR dose state may perform accurate time synchronization. In addition, the WUR Beacon frame may be transmitted periodically. At this time, the transmission period of the WUR beacon frame may be longer than the transmission period of the PCR beacon frame.

The WUR Beacon frame may include information about the aforementioned BSS. For example, the WUR beacon frame may signal the same information as the information signaled by the PCR beacon frame transmitted through PCR. The WUR Beacon frame may include a legacy part and a WUR part like the wake-up frame. The legacy part of the WUR beacon frame may have the same role and structure as the legacy part of the wake-up frame. The WUR part of the WUR Beacon frame may include identifier information of the base wireless communication terminal.

In addition, the WUR Beacon frame may not include the identifier of the intended recipient of the WUR Beacon frame, but may include a TXID that identifies the base wireless communication terminal transmitting the WUR Beacon frame. In more detail, the ID field of the WRU beacon frame may indicate the TXID of the base wireless communication terminal transmitting the WUR beacon frame. In addition, when the wireless communication terminal receives the WUR beacon frame, the wireless communication terminal may not wake up the PCR transceiver. This is because when the wireless communication terminal receives the WUR beacon frame, it may not be necessary to perform active scanning of the PCR transceiver.

When there is no data to be transmitted to the base wireless communication terminal by the wireless communication terminal in the PCR dose state, the wireless communication terminal may turn off the WURx based on the WUR beacon frame transmission period. In detail, when the wireless communication terminal in the PCR dose state has no data to transmit to the base wireless communication terminal, the wireless communication terminal keeps the WURx turned on in the time interval in which the WUR beacon frame is transmitted, and turns off the WURx in the remaining time interval. can do. The operation of such a wireless communication terminal is WUR duty-cycle operation, and the operation mode of such a wireless communication terminal may be referred to as WUR duty-cycle mode.

In addition, a state in which the wireless communication terminal turns off the WURx may be referred to as a WUR doze state or a deep sleep state. When the base wireless communication terminal has data to be transmitted through PCR to the wireless communication terminal of the WUR duty-cycle mode, the base wireless communication terminal may transmit a wake-up frame to the corresponding wireless communication terminal immediately after transmitting the WUR beacon frame. In addition, when the base wireless communication terminal has data to be transmitted through PCR to the wireless communication terminal of the WUR duty-cycle mode, the base wireless communication terminal generates a TIM (Traffic Indication Map) indicating that there is data to be transmitted through the WUR beacon frame Can transmit

When the wireless communication terminal does not receive the WUR beacon frame for a predetermined time from the time when the wireless communication terminal enters the PCR dose state, the wireless communication terminal may wake up the PCR transceiver. In this case, when the wireless communication terminal does not receive the PCR beacon frame from the base wireless communication terminal connected to the corresponding wireless communication terminal through PCR, the wireless communication terminal may perform a scanning operation. In more detail, the wireless communication terminal may transmit a probe request frame through PCR. If the TXID of the received WUR beacon frame is different from the TXID of the base wireless communication terminal combined with the wireless communication terminal, the wireless communication terminal may wake up the PCR transceiver.

In the embodiment of FIG. 19, the AP periodically transmits a WUR Beacon frame. A station in WUR duty-cycle mode maintains a WURx turn-on in accordance with the transmission period of the WUR beacon frame, and WURx dose otherwise. If the AP has data to send to the station via PCR, the AP sends a wake-up frame to the station immediately after transmitting the WUR beacon frame. The station receives the wake-up frame and wakes up the PCR transceiver.

20 is a diagram illustrating a method for transmitting a WUR A-beacon according to an embodiment of the present invention. According to an embodiment, the wireless communication terminal may estimate WUR identifiers corresponding to the OBSS based on the TXID included in the OBSS WUR beacon frame transmitted by the base wireless communication terminal of the OBSS. This is because the WUR identifiers identifying the wireless communication terminals of the OBSS may be a value adjacent to the TXID of the base wireless communication terminal of the OBSS. Accordingly, when the base radio communication terminal of the OBSS uses the same TXID as the base radio communication terminal of the BSS to which the radio communication terminal belongs, the radio communication terminal is a base radio communication terminal having a different TXID of the base radio communication terminal from the base radio communication terminal. It may report that it is a duplicate of TXID of. In addition, the wireless communication terminal may request to change the TXID or WUR STA ID.

The wireless communication terminal may be difficult to determine the validity of the OBSS WUR beacon frame. This is because the wireless communication terminal cannot recognize the embedded BSSID of the base wireless communication terminal of the OBSS based on the WUR beacon frame transmitted from the OBSS. According to an embodiment of the present invention, the base wireless communication terminal may transmit a WUR beacon frame to wireless communication terminals belonging to the OBSS, not the BSS operated by the base wireless communication terminal. At this time, the WUR beacon frame may include the TXID of the base wireless communication terminal. For example, the base radio communication terminal may transmit a WUR Advertisement Beacon frame (hereinafter referred to as a WUR A-beacon) to which the TXID of the base radio communication terminal is inserted to wireless communication terminals belonging to the OBSS. have.

The WUR A-beacon may include an FCS that does not use an embedded BSSID or performs CRC using a preset embedded BSSID value (for example, all zeros embedded BSSID). This is because at least some of the wireless communication terminals may not recognize the embedded BSSID value of the base wireless communication terminal transmitting the WUR A-beacon. In addition, the WUR A-beacon may include information for distinguishing the W-UR beacon frame and the A-beacon received by the wireless communication terminal from the BSS of the wireless communication terminal. For example, the WUR A-beacon may further include information indicating the type of WUR A-beacon. The base wireless communication terminal may generate a WUR A-beacon by inserting a predetermined value into some of the fields included in the WUR beacon frame. In addition, the base wireless communication terminal may transmit the WUR A-beacon to the wireless communication terminals of the OBSS. Specifically, the base wireless communication terminal may insert a predetermined value (for example, a value of all bits '0') other than partial TSF information at a position where partial TSF information included in the WUR beacon frame is inserted. . In the WUR A-beacon inserted with the preset value in the partial TSF position, the received wireless communication terminal may determine the validity of the WUR A-beacon through FCS calculation. In addition, the wireless communication terminal may obtain the TXID of the base wireless communication terminal of the OBSS indicated by the WUR A-beacon. The WUR A-beacon may be continuously transmitted with the WUR Beacon frame according to the WUR Beacon frame transmission period of the base wireless communication terminal. According to another embodiment, the WUR A-beacon may be transmitted in place of the corresponding WUR beacon frame at the time when the WUR beacon frames in a predefined order are transmitted. According to another embodiment, the WUR A-beacon may be transmitted based on a separate WUR A-beacon period, regardless of the period of the WUR Beacon frame. Alternatively, the base wireless communication terminal may transmit the WUR A-beacon at any time if necessary. Additionally, when the base wireless communication terminal uses two or more TXIDs, the base wireless communication terminal may insert all TXIDs used by the base wireless communication terminal into the WUR A-beacon and transmit the same.

21 is a diagram illustrating a method for reporting a superimposed WUR identifier by a wireless communication terminal according to one embodiment of the present invention. As described above with reference to FIG. 20, the wireless communication terminal may acquire the OBSS TXID of the base wireless communication terminal of the OBSS. In addition, the wireless communication terminal may obtain range information of the WUR identifier used in the OBSS based on the OBSS TXID. The wireless communication terminal may determine whether the WUR identifiers used in the OBSS overlap with the WUR identifier used in the BSS to which the wireless communication terminal belongs based on the range information of the WUR identifier used in the OBSS. In addition, the wireless communication terminal may report the overlapping information to the base wireless communication terminal based on the determination result. For example, when at least some of the WUR identifiers used in the OBSS overlap with the WUR identifier used in the BSS to which the wireless communication terminal belongs, the wireless communication terminal may report the overlapping WUR identifier to the base wireless communication terminal. The wireless communication terminal can report the overlapping WUR identifier to the base wireless communication terminal to induce the base wireless communication terminal to change the WUR identifier associated with the base wireless communication terminal. When the base wireless communication terminal receives a report on the overlapping WUR identifier, the base wireless communication terminal may change the WUR identifier associated with the base wireless communication terminal.

According to an embodiment, the overlapping information may be transmitted through an event report frame. Specifically, the wireless communication terminal may generate an event report frame including the overlapping information by inserting information indicating the WUR ID duplication into the Event Type field of the event report frame. In addition, the wireless communication terminal may transmit an event report frame including overlapping information to the base wireless communication terminal. In addition, the event report element of the event report frame may include at least one overlapped WUR ID that is determined to overlap.

According to another embodiment, the event report element of the event report frame may include a TXID bitmap indicating the TXIDs. In this case, the TXID bitmap may be a bitmap in which an OBSS TXID included in at least one WUR A-beacon received by the wireless communication terminal is displayed. Alternatively, the TXID bitmap may be a bitmap in which the BSSID of the OBSS received by the wireless communication terminal through the PCR transceiver is displayed. On the other hand, the base wireless communication terminal receiving the event report frame may respond with a response frame (Ack). Also, the base wireless communication terminal may request transmission of an event report frame from a specific wireless communication terminal among a plurality of wireless communication terminals associated with the base wireless communication terminal. In this case, the request and transmission of the event report frame may be transmitted and received through PCR.

22 illustrates a structure of a WUR ID element according to an embodiment of the present invention. The wireless communication terminal may acquire a WUR STA ID of the wireless communication terminal, a WUR group ID for identifying a group to which the wireless communication terminal belongs, and a TXID of the base wireless communication terminal combined with the wireless communication terminal in the WUR mode negotiation process. Then, when a change to the WUR identifier is required, the wireless communication terminal and the base wireless communication terminal can update the WUR identifier using an action frame (eg, WUR ID Action Frame). In more detail, the WUR ID Action frame may include a WUR ID element. In addition, the WUR ID Action frame may include a Reason field indicating a reason for transmitting the frame. For example, the Reason field of the WUR ID Action frame may include information indicating that a WUR identifier of a value duplicated with the WUR identifier in the corresponding BSS is used in the OBSS. In addition, the Reason field may include information indicating whether the WUR identifier used repeatedly is one of a TXID, a WUR STA ID, and a WUR group ID of the BSS.

The WUR ID element may follow the format of a general extension element of the 802.11 standard. In addition, the WUR ID element may include fields indicating each of an ID ID field, a Length field, and a TXID, a WUR STA ID, and a WUR group ID. According to an embodiment, the WUR group ID field indicating the WUR group ID may include at least one WUR group ID to which the wireless communication terminal belongs. According to another embodiment, the WUR group ID field may include a starting group ID and a group ID bitmap. In this case, as described above, the group ID bitmap may have a form indicating a bit corresponding to the WUR group ID of the group to which the wireless communication terminal belongs. Also, the wireless communication terminal may determine the size of the group ID bitmap based on the length value of the action frame. According to another embodiment, the WUR group ID field may include a plurality of group ID bitmaps. In this case, the WUR group ID field may include one starting group ID. By doing so, it is possible to prevent an excessively large size of one group ID bitmap.

The wireless communication terminal operating in the WUR mode detects an attack targeting the WUR STA ID of the wireless communication terminal or the WUR group ID including the wireless communication terminal from the outside, or the WUR identifiers associated with the wireless communication terminal in the external WUR BSS. It can be detected that the same WUR identifier is used. In this case, the wireless communication terminal may transmit a WUR ID Request Action frame in which the WUR Action field is set to WUR ID Request to the base wireless communication terminal through the PCR transceiver. At this time, the WUR ID Request Action frame may not include a WUR ID element. The WUR ID Request Action frame may include a WUR identifier requesting a change in place of the WUR ID element. While the wireless communication terminal operates in the WUR mode, the WUR STA ID may be periodically changed, and when the WUR STA ID change cycle arrives, the wireless communication terminal may transmit a WUR ID Request Action frame for changing the WUR STA ID. .

When the base wireless communication terminal receives the WUR ID Request Action frame from the wireless communication terminal, the base wireless communication terminal may transmit an immediate response frame (Ack). Next, the base wireless communication terminal may transmit a WUR ID Response Action frame to the wireless communication terminal through a TXOP of a later time. The WUR ID Response Action frame may include a WUR ID element. In addition, the WUR ID element may include a changed WUR identifier for all of the WUR identifiers for which a change is included in the WUR ID Request Action frame. When the wireless communication terminal receives the WUR ID Response Action frame from the base wireless communication terminal, the wireless communication terminal may acknowledge with an immediate response frame. In addition, the wireless communication terminal may update the WUR identifiers based on the received WUR ID element.

Also, the base wireless communication terminal detects an attack on the wireless communication terminal corresponding to a specific WUR STA ID or WUR group ID from the outside, or is identical to the WUR identifiers used in the BSS operated by the base wireless communication terminal in the external WUR BSS. It can be detected that a WUR identifier is used. In this case, the base wireless communication terminal may transmit a WUR ID Response Action frame including the changed WUR identifier to the corresponding wireless communication terminals. The WUR ID element described above may be transmitted and received through PCR like other action frames described above. Thus, the operation of inducing wake-up of the wireless communication terminal can be preceded.

Hereinafter, power save operations of the wireless communication terminal according to an embodiment of the present invention will be described by dividing them into operations according to a power management subfield and operations using WUR.

23 is a diagram illustrating a power save operation of a wireless communication terminal according to an embodiment of the present invention. In a conventional WLAN, when a wireless communication terminal uses a power management function, the terminal may operate in two modes, an active mode and a power save (PS) mode. In the active mode, the wireless communication terminal always stays awake. When the wireless communication terminal is in the PCR dose state, since the wireless communication terminal cannot receive a frame transmitted by the base wireless communication terminal, the base wireless communication terminal should be able to determine whether the wireless communication terminal is in the PCR dose state. Therefore, the base wireless communication terminal can record which of the active mode and the PS mode the wireless communication terminal connected to the base wireless communication terminal. For this purpose, when the wireless communication terminal switches the mode of the power management, the wireless communication terminal signals the mode change of the power management by setting a value of the Power Management (PM) subfield of the Frame Control field of the data transmitted by the wireless communication terminal. can do.

After completion of the transmission sequence initiated by the wireless communication terminal, the wireless communication terminal can switch the power management mode. In addition, the wireless communication terminal may be limited to switching the power management mode using a transmission sequence requesting an immediate response. When the wireless communication terminal transmits data in which the PM subfield is set to 1 and receives an immediate response (ex: ACK frame, BA frame) for the data, the wireless communication terminal may start a power save mode operation. In addition, when the wireless communication terminal transmits data in which the PM subfield is set to 0 and receives an immediate response (ex: ACK frame, BA frame) for the data, the wireless communication terminal may start an active mode operation.

The existing WLAN standard defines a number of detailed protocols in power save mode operation. Among many detailed protocols, normal power save mode and unscheduled automatic power save delivery (U-APSD) are protocols that do not require a separate scheduling process.

In the power save mode, uplink transmission of the wireless communication terminal may be unlimited. In the power save mode, the wireless communication terminal may attempt to transmit to the PCR awake state at any time by switching to the PCR awake state. However, when the base wireless communication terminal performs the downlink transmission, if the wireless communication terminal is in the PCR dose state, the downlink transmission cannot be received. Accordingly, the normal power save mode and the U-APSD define operations of the wireless communication terminal and the base wireless communication terminal based on the downlink transmission situation.

When the wireless communication terminal switches from the active mode to the PS mode in the normal power save mode, the base wireless communication terminal cannot directly transmit data to the corresponding wireless communication terminal. The base wireless communication terminal stores data to be transmitted to the wireless communication terminal in a buffer. Thereafter, the base wireless communication terminal signals that there is data to be transmitted to the terminal using the TIM element of the beacon frame. When the wireless communication terminal in the PS mode receives the beacon frame in the awake state, and the bit corresponding to the AID of the wireless communication terminal of the TIM element indicates that there is data to be transmitted, the wireless communication terminal transmits the PS- to the base wireless communication terminal. You can send poll frames. In this case, the wireless communication terminal may perform the EDCA backoff in the AC_BE class to transmit the PS-poll frame. The base wireless communication terminal receiving the PS-poll frame may transmit one of an ACK frame or a DL buffered unit (BU) to the corresponding wireless communication terminal. The wireless communication terminal receiving the ACK frame should remain awake until the base wireless communication terminal transmits the BU in a new TXOP (Transmit Opportunity). If the More Data field of the BU transmitted by the base wireless communication terminal is activated, the wireless communication terminal should transmit the PS-poll frame again. The wireless communication terminal should check the beacon frame every period designated by a delivery traffic indication map (DTIM) period.

Whether the wireless communication terminal uses U-APSD may be set for each AC in a link establishment step such as a (re) connection step. The AC of the wireless communication terminal using the U-APSD is set to trigger-enabled AC. The corresponding AC of the base radio communication terminal is considered to be a transceiver-enabled AC. The wireless communication terminal may not confirm the AC corresponding to the trigger-enabled AC in the TIM element. The wireless communication terminal may start a service period by transmitting a trigger frame at any point in time and trigger DL buffered BU transmission. At this time, the trigger frame is one of the QoS data or the null frame transmitted from the trigger-enabled AC. The service interval for the corresponding wireless communication terminal starts from the time when the immediate response to the trigger frame transmitted by the wireless communication terminal is received. The base wireless communication terminal may transmit the buffered BU in the service interval. Therefore, the wireless communication terminal must maintain the awake state until the end point of the end of the service period (OSP) is activated in the BU transmitted by the base wireless communication terminal. If the wireless communication terminal uses U-APSD for some AC, it is not indicated by the TIM whether there is a buffered BU of that AC. Only the presence of a buffered BU of an AC that does not use U-APSD is indicated in the TIM. Therefore, the wireless communication terminal must check the TIM in order to receive the buffered BU of the AC that does not use the U-APSD, and must follow the operation of the normal power save mode.

In an embodiment of FIG. 23A, the station receives data corresponding to AC_VO and AC_VI using U-APSD. The station starts a service interval by sending a trigger frame to the AP. The station receives an ACK frame for the trigger frame from the AP. The AP transmits QoS data corresponding to AC_VO and QoS data corresponding to AC_VI to the station. The station remains awake until the service interval ends.

In the embodiment of FIG. 23 (b), the station receives data corresponding to AC_BE through the normal PS mode. The station receives the beacon frame from the AP and confirms that the bit of the TIM corresponding to the AID of the station is activated. The station transmits a PS-poll frame to the AP and receives a BU or ACK frame from the AP. If the station receives an ACK frame for the PS-poll frame, it stays awake until it receives QoS data from the AP. Upon receiving the QoS data, the station may send an ACK frame and again enter the PCR dose state.

24 is a diagram illustrating a detailed operation of wake-up of a wireless communication terminal according to an embodiment of the present invention. The wireless communication terminal in the PCR dose state cannot detect a frame transmitted through PCR. Therefore, when the wireless communication terminal in the PCR dose state wakes up in the PCR dose state, the wireless communication terminal may access the channel without considering the hidden-node. Therefore, the wireless communication terminal may attempt transmission after a wake-up in the PCR dose state is detected after a frame or PPDU capable of setting the NAV. According to a specific embodiment, the wireless communication terminal may suspend the transmission attempt until a frame for setting the NAV is detected after a wake-up in the PCR dose state or a predetermined time elapses. In this case, the predetermined time may be referred to as NAVSyncDelay. For example, the wireless communication terminal transmits when a frame capable of setting the NAV until a predetermined time after performing a clear channel assembly (CCA) until a predetermined time after waking up in the PCR dose state is transmitted. You can try The transmission attempt may indicate access to the channel in accordance with the channel access procedure. According to one embodiment, the wireless communication terminal receives a wake-up frame from the base wireless communication terminal in a PCR dose state. In response to the wake-up frame, the wireless communication terminal turns on the PCR transceiver. The wireless communication terminal may attempt to transmit after performing CCA until a NAVSyncDelay has elapsed from when a frame capable of setting NAV is received or from wake-up.

A wireless communication terminal that attempts to transmit after a wake-up in the PCR dose state may need to perform a backoff operation according to an EDCA (Enhaced Distributed Channel Access) rule. In the conventional WLAN operation, the wireless communication terminal receives a primitive called MA-UNITDATA.request from the upper layer and starts a backoff operation according to the EDCA rule. A wireless communication terminal that attempts to transmit after a wake-up in the PCR dose state may receive a MA-UNITDATA.request from a higher layer by a WUR MAC layer operating separately from the PCR MAC layer. Therefore, the PCR MAC layer may not receive the MA-UNITDATA.request primitive. The WUR MAC layer may store the MA-UNITDATA.request primitive and transmit the MA-UNITDATA.request primitive to the PCR MAC layer until the PCR transceiver is turned on. In another specific embodiment, there may be a MAC Service Access Point (SAP) connecting the PCR MAC layer and the WUR MAC layer. At this time, when the PCR MAC layer wakes up, the MAC SAP may transmit MA-UNITDATA.request to the PCR MAC layer.

According to an embodiment, the wireless communication terminal may perform unsolicited UL without receiving a wake-up frame from the base. In this case, it is difficult for the base wireless communication terminal to recognize that the wireless communication terminal is in the PCR operation state for the time required for the PCR switching delay and the channel connection of the wireless communication terminal. The time taken for channel access may include the initial NAV setup after wake-up and the time spent for the contention procedure in EDCA. Accordingly, when the downlink data to be transmitted to the corresponding wireless communication terminal is buffered in the base wireless communication terminal, the base wireless communication terminal may transmit a wake-up frame to the wireless communication terminal. At this time, when the power of the WURx of the wireless communication terminal is turned off, the wireless communication terminal cannot receive the wake-up frame transmitted from the base wireless communication. In addition, additional overhead may occur due to a wake-up frame transmission failure. The wireless communication terminal according to an embodiment of the present invention may maintain power of the WURx of the wireless communication terminal until at least the response of the base wireless communication terminal for the uplink transmission.

According to an embodiment, when the uplink data transmitted by the wireless communication terminal is a data frame that does not request an immediate response, the wireless communication terminal may maintain the power of the WURx until the uplink data transmission is completed. Alternatively, the wireless communication terminal may maintain the power of the WURx until a time point of accessing the channel to start uplink data transmission. According to another embodiment, when the wireless communication terminal is in the WUR duty-cycle mode, the above rule may be excluded. In addition, when the above-described WURx power maintenance condition and the WUR duty-cycle on duration overlap, the wireless communication terminal may determine the WURx until the later time between the end of the on-duration and the end of the power maintenance according to the aforementioned WURx power maintenance condition. Power can be maintained.

Hereinafter, the WUR duty-cycle operation of the wireless communication terminal will be described in detail with reference to FIG. 25. 25 is a diagram illustrating WUR duty-cycle operation of a wireless communication terminal according to an embodiment of the present invention. As described above, the wireless communication terminal can designate the duty cycle of the WURx to maintain the WURx in the on duration negotiated with the base wireless communication terminal. In addition, in the off-duration, the wireless communication terminal may maintain both the PCR transceiver and the WURx in a turn off state. The wireless communication terminal may maintain duty-cycle in the WUR based power save mode. In the embodiment of FIG. 25A, the station performs a WUR duty-cycle operation. When the AP transmits a WUR Beacon frame, the station remains on duration to receive the WUR Beacon frame. Since the station takes a certain time to turn on the WURx, the station may send a turn on command to the WURx before the start of the on-duration in consideration of the time when the WURx is turned on.

In addition, the base wireless communication terminal and the wireless communication terminal can exchange information about the duty-cycle parameters. This is because the base wireless communication terminal can transmit a WUR frame to the wireless communication terminal in the duration. In more detail, the wireless communication terminal and the base wireless communication terminal may exchange information on a duty cycle parameter using a WUR mode element. The information on the duty-cycle parameter includes the duty-cycle basic unit information, minimum wake time information, duty-cycle on duration information, duty-cycle interval information, and duty-cycle start time information described above. It may include at least one of. The duty-cycle on duration may be greater than or equal to the minimum wake time.

The cycle of the duty cycle may be different for each wireless communication terminal. The duty cycle may be set to a multiple of the basic unit. In this case, the basic unit may be determined by the base wireless communication terminal. In another specific embodiment, the basic unit may be a predetermined value. In addition, the basic unit may be set based on the transmission period of the WUR beacon frame. Since the wireless communication terminal receives the WUR beacon frame according to the duty-cycle period, the wireless communication terminal may not receive all the WUR beacon frames transmitted by the base wireless communication terminal. Also, since the duty cycle may be different for each wireless communication terminal, the set of wireless communication terminals that maintain on-duration to receive the corresponding WUR beacon frame may be different each time the WUR beacon frame is transmitted. have.

When the wireless communication terminal receives the WUR frame transmitted to another wireless communication terminal or the corresponding wireless communication terminal in the on duration in which the wireless communication terminal is expected to receive the WUR beacon frame, the wireless communication terminal receives the WUR beacon frame as the reception of the WUR beacon frame. Can be considered.

In the embodiment of FIG. 25B, the first station STA1, the second station STA2, and the third station STA3 operate in WUR duty-cycle mode. The duty cycle of each of the first station STA1, the second station STA2, and the third station STA3 is different. When the AP transmits the first WUR beacon frame, the first station STA1, the second station STA2, and the third station STA3 receive the WUR beacon frame. When transmitting the second WUR Beacon frame, the second station STA2 receives the WUR Beacon frame. When transmitting the third WUR Beacon frame, the third station STA3 receives the WUR Beacon frame. In addition, when the AP transmits a wake-up frame to the second station STA2, the first station STA1 maintains on duration. The first station STA2 considers the wake-up frame transmitted to the second station STA2 as a WUR beacon frame.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be interpreted as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (20)

In a wireless communication terminal for communicating wirelessly, A first wireless transceiver for transmitting and receiving a signal through a first waveform; A second wireless receiver configured to receive a signal through a second waveform different from the first waveform; And a processor, The processor, Receiving a first wake-up radio frame from the base wireless communication terminal of a basic service set (BSS) to which the wireless communication terminal belongs, through the second wireless receiver; When the identifier field of the first WUR frame indicates a sender ID for identifying the base wireless communication terminal, the wireless communication terminal determines whether the BSS corresponds to a BSS corresponding to a multiple BSS identifier (BSSID) set. Determine whether it is the intended recipient of the first WUR frame, If the wireless communication terminal is the intended recipient of the first WUR frame, the first wireless transceiver to wake up based on the first WUR frame, The multi-BSSID set includes a BSSID of each of a plurality of BSSs operated by one base wireless communication terminal. According to claim 1, The processor, If the BSS to which the wireless communication terminal belongs does not correspond to the multiple BSSID set, it is determined that the wireless communication terminal is an intended recipient of the first WUR frame, If the BSS to which the wireless communication terminal belongs corresponds to any one of at least one untransmitted BSSID included in the multiple BSSID set, it is determined that the wireless communication terminal is not the intended recipient of the first WUR frame, The multi-BSSID set is composed of one transmitting BSSID and at least one untransmitted BSSID, the transmitting BSSID is a representative BSSID used for transmission of a management frame for all of the plurality of BSSs operated by the base wireless communication terminal, Transmission of the management frame is performed through the first waveform, And the at least one untransmitted BSSID is a BSSID excluding a transmitting BSSID among BSSIDs constituting the multiple BSSID set. The method of claim 2, When the BSS to which the wireless communication terminal belongs corresponds to any one of the untransmitted BSSIDs included in the multiple BSSID set, The processor, And determining whether the wireless communication terminal is an intended recipient of the first WUR frame based on an untransmitted ID identifying the BSS to which the wireless communication terminal belongs. The method of claim 3, wherein The processor, And a non-transmitting ID for identifying a BSS to which the wireless communication terminal belongs based on the sender ID. The method of claim 4, wherein The processor, Receiving BSSID index information corresponding to the BSS to which the wireless communication terminal belongs, through the first wireless transceiver, And acquiring the untransmitted ID based on the BSSID index information corresponding to the BSS to which the wireless communication terminal belongs and the sender ID. The method of claim 5, BSSID index information corresponding to the BSS to which the wireless communication terminal belongs represents any one of integers from 1 to K, The processor, And if the identifier field of the first WUR frame represents the sender ID plus a value indicated by the BSSID index information, determine that the wireless communication terminal is an intended recipient of the first WUR frame. The method of claim 6, K denotes the number of untransmitted BSSIDs among BSSIDs constituting the multiple BSSID set. The method of claim 7, wherein The processor, Acquires the transmission BSSID through the first radio transceiver; And obtaining the sender ID based on the transmitting BSSID. The method of claim 8, And the transmitter ID is a value set based on a predetermined number of least significant bits (LSBs) among a plurality of bits constituting the transmission BSSID. According to claim 1, The processor, Receiving a second WUR frame periodically transmitted through the second wireless receiver, If the frame type field of the second WUR frame indicates a beacon, determining whether the wireless communication terminal is an intended recipient of the second WUR frame based on the identifier field of the second WUR frame and the sender ID. and, If the wireless communication terminal is an intended recipient of the second WUR frame, perform a subsequent operation indicated by the second WUR frame based on the second WUR frame. The method of claim 10, The processor, If the identifier field of the second WUR frame includes the sender ID, determine that the wireless communication terminal is an intended recipient of the second WUR frame, If the wireless communication terminal is an intended recipient of the second WUR frame, updating time information of the wireless communication terminal. The method of claim 3, wherein And when the identifier field of the first WUR frame indicates the untransmitted ID, the first WUR frame is a WUR frame broadcast over the second waveform in a BSS to which the wireless communication terminal belongs. According to claim 1, The identifier field of the first WUR frame includes one identifier represented by a predetermined number of bits. Wherein the first WUR frame is a fixed length frame that does not include an additional field including an identifier other than the identifier field. The method of claim 13, The preset number is 12, the wireless communication terminal. According to claim 1, The processor, If the wireless communication terminal is not the intended recipient of the first WUR frame, stops receiving the first WUR frame, When the wireless communication terminal is an intended receiver of the first WUR frame, a frame check sequence (FCS) value is generated based on values of a plurality of fields included in the first WUR frame, Determining whether the first WUR frame is valid based on the generated FCS value and a value included in the FCS field of the first WUR frame, And when the first WUR frame is valid, wakes up the first wireless transceiver based on the first WUR frame. A method of operating a wireless communication terminal for transmitting and receiving a signal through a first waveform and receiving a signal through a second waveform different from the first waveform, Receiving a WUR frame (wake-up radio frame) through the second waveform from a base wireless communication terminal of a basic service set (BSS) to which the wireless communication terminal belongs; When the identifier field of the WUR frame indicates a sender ID for identifying the base wireless communication terminal, the wireless communication terminal determines whether the WUR frame corresponds to a BSS corresponding to a set of BSS identifiers (BSSIDs). Determining if the intended recipient of the; And If the wireless communication terminal is an intended recipient of the WUR frame, waking up the wireless communication terminal based on the WUR frame, The multiple BSSID set includes a BSSID of each of a plurality of BSSs operated by one base wireless communication terminal. The method of claim 16, Determining whether the wireless communication terminal is the intended recipient of the WUR frame, If the BSS to which the wireless communication terminal belongs does not correspond to the multiple BSSID set, it is determined that the wireless communication terminal is an intended recipient of the WUR frame, and the BSS to which the wireless communication terminal belongs includes the multiple BSSID set. If it corresponds to any one of an untransmitted BSSID, the wireless communication terminal includes determining that it is not an intended recipient of the WUR frame, The multi-BSSID set is composed of one transmitting BSSID and at least one untransmitted BSSID, the transmitting BSSID is a representative BSSID used for transmission of a management frame for all of the plurality of BSSs operated by the base wireless communication terminal, Transmission of the management frame is performed through the first waveform, The at least one unsent BSSID is a BSSID wireless communication terminal excluding a transmitting BSSID among BSSIDs constituting the multi-BSSID set. The method of claim 17, Determining whether the wireless communication terminal is the intended recipient of the WUR frame, When the BSS to which the wireless communication terminal belongs corresponds to any one of the untransmitted BSSIDs included in the multiple BSSID set, Determining whether the wireless communication terminal is an intended recipient of the WUR frame based on an untransmitted ID identifying the BSS to which the wireless communication terminal belongs. The method of claim 18, The method, Obtaining an unsent ID identifying a BSS to which the wireless communication terminal belongs based on the sender ID. The method of claim 19, Acquiring the untransmitted ID, Receiving BSSID index information corresponding to a BSS to which the wireless communication terminal belongs via the first waveform; And Acquiring the untransmitted ID based on the BSSID index information corresponding to the BSS and the sender ID.

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